Integrated circuit with laminated magnetic core inductor and magnetic flux closure layer

ABSTRACT

A structure comprises a semiconductor integrated circuit, an inductor, and a magnetic flux closure layer. The inductor is integrated into a multilevel wiring network in the semiconductor integrated circuit. The inductor includes a planar laminated magnetic core and a conductive winding that turns around in a generally spiral manner on the outside of the planar laminated magnetic core. The planar laminated magnetic core includes an alternating sequence of a magnetic layer and a non-magnetic layer. The magnetic flux closure layer is disposed within about 100 μm of a face of the planar laminated magnetic core, the face of the planar magnetic core parallel to a principal plane of the planar laminated magnetic core. A second magnetic flux closure layer can be disposed within about 100 μm of an opposing face of the planar laminated magnetic core.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 14/991,111, filed on Jan. 8, 2016, titled “Magnetic CoreInductor Integrated with Multilevel Wiring Network,” which is acontinuation of U.S. patent application Ser. No. 14/517,370, filed onOct. 17, 2014, now U.S. Pat. No. 9,357,651, titled “Magnetic CoreInductor Integrated with Multilevel Wiring Network,” which is adivisional application of U.S. application Ser. No. 13/609,391, filed onSep. 11, 2012, now U.S. Pat. No. 9,844,141, titled “Magnetic CoreInductor Integrated with Multilevel Wiring Network.” This application isalso related to U.S. patent application Ser. No. 13/613,011, filed onSep. 13, 2012, now U.S. Pat. No. 9,357,650, titled “Magnetic CoreInductor Integrated with Multilevel Wiring Network.” The foregoingapplications are hereby incorporated by reference.

BACKGROUND

The present invention relates to electronic devices of very large scaleintegration circuits. In particular, it relates to devices that deliverpower supply voltages for the circuits.

SUMMARY

Example embodiments described herein have innovative features, no singleone of which is indispensable or solely responsible for their desirableattributes. The following description and drawings set forth certainillustrative implementations of the disclosure in detail, which areindicative of several exemplary ways in which the various principles ofthe disclosure may be carried out. The illustrative examples, however,are not exhaustive of the many possible embodiments of the disclosure.Without limiting the scope of the claims, some of the advantageousfeatures will now be summarized. Other objects, advantages and novelfeatures of the disclosure will be set forth in the following detaileddescription of the disclosure when considered in conjunction with thedrawings, which are intended to illustrate, not limit, the invention.

An aspect of the invention is directed to a structure comprising: asemiconductor integrated circuit comprising a multilevel wiring networkdisposed on a substrate; an inductor integrated into said multilevelwiring network, said inductor comprising a planar laminated magneticcore and a conductive winding that turns around in a generally spiralmanner on the outside of said planar laminated magnetic core, saidplanar laminated magnetic core comprising an alternating sequence of amagnetic layer and a non-magnetic layer; and a magnetic flux closurelayer disposed within about 100 μm of a face of the planar laminatedmagnetic core, the face of the planar magnetic core parallel to aprincipal plane of the planar laminated magnetic core.

In one or more embodiments, the conductive winding is disposed betweenthe planar laminated magnetic core and the magnetic flux closure layer.In one or more embodiments, the magnetic flux closure layer extendsacross a length and a width of the face of the planar laminated magneticcore, the length and the width measured with respect to the principalplane of the planar laminated magnetic core. In one or more embodiments,the magnetic flux closure layer extends beyond the length and the widthof the face of the planar laminated magnetic core. In one or moreembodiments, the face of the planar laminated magnetic core is furtheraway from the substrate than an opposing face of the planar laminatedmagnetic core. In one or more embodiments, the face of the planarlaminated magnetic core is closer to the substrate than an opposing faceof the planar laminated magnetic core.

In one or more embodiments, the face of the planar laminated magneticcore is closer to the substrate than the opposing face of the planarlaminated magnetic core; and wire segments in at least one wiring planein the multilevel wiring network are disposed between the inductor andthe substrate; the magnetic flux closure layer is disposed between theinductor and the wire segments in the at least one wiring plane. In oneor more embodiments, the magnetic flux closure layer provides a lowmagnetic reluctance path for an inductor magnetic flux. In one or moreembodiments, the magnetic flux closure layer prevents the inductormagnetic flux from passing through any wire segments in the at least onewiring plane.

In one or more embodiments, a thickness of the magnetic flux closurelayer is less than a total thickness of the planar laminated magneticcore, the thickness and the total thickness measured with respect to anaxis that is orthogonal to the principal plane of the planar laminatedmagnetic core. In one or more embodiments, a first thickness of themagnetic flux closure layer is less than or equal to a second thicknessof each magnetic layer, the first and second thicknesses measured withrespect to an axis that is orthogonal to the principal plane of theplanar laminated magnetic core. In one or more embodiments, the secondthickness of each magnetic layer is the same. In one or moreembodiments, the magnetic flux closure layer comprises the same materialas the magnetic layers.

In one or more embodiments, the planar laminated magnetic core and themagnetic flux closure layer are configured so that a magnetic fluxpasses through a first magnetic layer in the planar laminated magneticcore in a first direction that is parallel to a first hard axis ofmagnetization of the first magnetic layer and the magnetic flux passesthrough the magnetic flux closure layer in a second direction that isparallel to a second hard axis of magnetization of the magnetic fluxclosure layer. In one or more embodiments, each magnetic layer in theplanar laminated magnetic core comprises a first anisotropic magneticmaterial and the magnetic flux closure layer comprises a secondanisotropic magnetic material, the first and second anisotropic magneticmaterials having a respective hard axis of magnetization that is atleast partially aligned with an axis of the conductive winding, theconductive winding extending along the axis of the conductive winding.In one or more embodiments, the first anisotropic magnetic material isthe same as the second anisotropic magnetic material.

Another aspect of the invention is directed to a structure comprising: asemiconductor integrated circuit comprising a multilevel wiring networkdisposed on a substrate; an inductor integrated into said multilevelwiring network, said inductor comprising a planar laminated magneticcore and a conductive winding that turns around in a generally spiralmanner on the outside of said planar laminated magnetic core, saidplanar laminated magnetic core comprising an alternating sequence of amagnetic layer and a non-magnetic layer; a first magnetic flux closurelayer disposed within about 100 μm of a face of the planar laminatedmagnetic core; and a second magnetic flux closure layer disposed withinabout 100 μm of an opposing face of the planar laminated magnetic core,the face and the opposing face parallel to a principal plane of theplanar laminated magnetic core.

In one or more embodiments, the conductive winding is disposed betweenthe planar laminated magnetic core and each magnetic flux closure layer.In one or more embodiments, the first magnetic flux closure layerextends across a length and a width of the face of the planar laminatedmagnetic core and the second magnetic flux closure layer extends acrossa length and a width of the opposing face of the planar laminatedmagnetic core, the respective length and the width measured with respectto the principal plane of the planar laminated magnetic core. In one ormore embodiments, the first magnetic flux closure layer extends beyondthe length and the width of the face of the planar laminated magneticcore. In one or more embodiments, the second magnetic flux closure layerextends beyond the length and the width of the opposing face of theplanar laminated magnetic core.

In one or more embodiments, the face of the planar laminated magneticcore is closer to the substrate than the opposing face of the planarlaminated magnetic core; wire segments in at least one wiring plane inthe multilevel wiring network are disposed between the inductor and thesubstrate; and the first magnetic flux closure layer is disposed betweenthe inductor and the wire segments in the at least one wiring plane. Inone or more embodiments, the first magnetic flux closure layer providesa low magnetic reluctance path for an inductor magnetic flux. In one ormore embodiments, the first magnetic flux closure layer prevents theinductor magnetic flux from passing through any wire segments in the atleast one wiring plane.

In one or more embodiments, the first and second magnetic flux closurelayers comprise the same material as the magnetic layers In one or moreembodiments, the planar laminated magnetic core and the first magneticflux closure layer are configured so that a first magnetic flux passesthrough a first magnetic layer in the planar laminated magnetic core ina first direction that is parallel to a first hard axis of magnetizationof the first magnetic layer and the first magnetic flux passes throughthe first magnetic flux closure layer in a second direction that isparallel to a second hard axis of magnetization of the first magneticflux closure layer. In one or more embodiments, the planar laminatedmagnetic core and the second magnetic flux closure layer are configuredso that a second magnetic flux passes through a second magnetic layer inthe planar laminated magnetic core in a third direction that is parallelto a third easy axis of magnetization of the second magnetic layer andthe second magnetic flux passes through the second magnetic flux closurelayer in a fourth direction that is parallel to a fourth easy axis ofmagnetization of the second magnetic flux closure layer.

In one or more embodiments, each magnetic layer in the planar laminatedmagnetic core comprises a first anisotropic magnetic material, the firstmagnetic flux closure layer comprises a second anisotropic magneticmaterial, and the second magnetic flux closure layer comprises a thirdanisotropic magnetic material, the first, second, and third anisotropicmagnetic materials having a respective hard axis of magnetization thatis at least partially aligned with an axis of the conductive winding,the conductive winding extending along the axis of the conductivewinding. In one or more embodiments, the first, second, and thirdanisotropic magnetic materials are the same.

IN THE DRAWINGS

These and other features of the present invention will become apparentfrom the accompanying detailed description and drawings, wherein:

FIG. 1 shows a schematic view of a planar magnetic core inductor withwindings on the outside;

FIG. 2A shows schematic top view of a plurality of inductors of planarmagnetic cores with end couplings, and with windings according to anembodiment of the disclosure;

FIG. 2B shows schematic top view of a plurality of planar magnetic coresdefining structural dimensions;

FIGS. 3A, 3B, 3C, and 3D show schematic cross-sectional views of planarmagnetic core inductors integrated into multilevel wiring networksaccording to various embodiments of the disclosure;

FIGS. 4A, 4B, and 4C show schematic cross-sectional views of steps inthe integration of a planar magnetic core into a multilevel wiringnetworks according to an embodiment of the disclosure;

FIG. 5 symbolically depicts a processor with a device that uses a planarmagnetic core inductor according to an embodiment of the disclosure;

FIG. 6 is a cross-sectional view of the laminated composition of aplanar magnetic core according to an embodiment of the disclosure;

FIG. 7 is a cross-sectional view of the laminated composition of aplanar magnetic core according to another embodiment of the disclosure;

FIG. 8A is a flow chart of a method for sputter depositing thenon-magnetic layers of a planar magnetic core according to an embodimentof the disclosure;

FIG. 8B is a flow chart of a method for manufacturing an inductoraccording to an embodiment of the disclosure.

FIGS. 9A and 9B show schematic views of embodiments for fabricatinglaminated planar magnetic cores and couplers by sputtering;

FIG. 10 shows a schematic view of fabricating laminated planar magneticcores and couplers by electroplating;

FIG. 11 is a cross-sectional view of a planar magnetic core in which thethicknesses of the magnetic and non-magnetic layers are co-optimized forlayer-to-layer magnetic flux closure, according to an embodiment of thedisclosure;

FIG. 12 is an exploded perspective view of the top surface of the planarmagnetic core illustrated in FIG. 11;

FIG. 13 is a cross-sectional view of a planar magnetic core that isfurther co-optimized for layer-to-layer magnetic flux closure, accordingto another embodiment of the disclosure;

FIG. 14 is a cross-sectional view of a planar magnetic core that isfurther configured for layer-to-layer magnetic flux closure, accordingto another embodiment of the disclosure;

FIG. 15 is a cross-sectional view of a planar magnetic core that isfurther configured for layer-to-layer magnetic flux closure, accordingto another embodiment of the disclosure;

FIG. 16 is a cross-sectional view of an inductor and magnetic fluxclosure layers according to one or more embodiments;

FIG. 17 is a cross-sectional view of an integrated circuit that includesthe inductor and magnetic flux closure layers illustrated in FIG. 16;

FIG. 18 illustrates a flow chart for a method of manufacturing aninductor according to an embodiment of the disclosure;

FIGS. 19 and 20 illustrate a flow chart for a method of manufacturing aninductor according to an embodiment of the disclosure; and

FIG. 21 illustrates a flow chart for a method of manufacturing aninductor according to an embodiment of the disclosure.

DETAILED DESCRIPTION

Microelectronics progress has been synonymous with decreasing featuresizes. Decreased feature sizes allow for ever higher circuit counts andincreased circuit densities for semiconductor integrated circuits (ICs).In today's very large scale integration (VLSI) technical art completeprocessors, even with multiple computing cores, are integrated onto asingle die, or chip. The terms “die” and “chip” are regarded asinterchangeable in the present disclosure. It is commonly understoodthat the vast number of devices in the ICs are in need of elaboratewiring networks for interconnecting devices, distributing power, andother functions known in the art. Such wiring networks are alsotypically integrated onto the same chips as the electronic components,such as the transistors. The wiring network is often referred to in theart as the back end of the line (BEOL) since its fabrication istypically done late in the processing sequences of a VLSI die.

As known in the art, the wiring network of a VLSI IC is usually ofmultiple levels, typically arranged into multiple discrete wiringplanes. Modern VLSI circuits are often in need of quite a few of suchwiring planes, typically in the range of 4 to 8, but with furtherintegration the number of wiring planes may increase to 10 and beyond.It is usual that the higher the planes are, that is the higher away fromthe semiconductor components, the bulkier and coarser the wires become.Wire segments on differing wiring planes may be interconnected by socalled Vertical Interconnect Accesses (VIAs). VIAs carry the electriccurrent in the direction perpendicular to that of the wiring planes.

Manufacturing of BEOL is well established in the VLSI arts. It isunderstood that there are a large number of steps involved in suchprocessing, and each step might have practically endless variationsknown to those skilled in the art. One multilevel wiring fabricationscheme often used in the art is the so-called damascene, or often dualdamascene, processing method. State of the art multilevel interconnectstructures typically use Cu as the metal for the wires and for the VIAs.

Semiconductor ICs may often be in need of inductors. Such may be thecase for analog, or mixed analog/digital circuits. Inductors are alsoneeded as transformers, and as energy storage elements. The use ofinductors as energy storage elements came to the fore because the energyconsumption of a chip may become a constraint on the performance in VLSIprocessors. A promising method to increase performance-per-watt ofdigital ICs may be the so called dynamic voltage and frequency scaling,where the supply voltage and/or clock frequency is adjusted transientlyto match required workloads.

A promising way to implement dynamic voltage scaling is to generate anddistribute multiple DC supply voltages for a semiconductor IC.Switched-inductor (buck) converters are good candidates for this tasksince they are capable of delivering high current densities in thenecessary voltage ranges. Such ranges may be, without intent oflimiting, between 2V and 0.35V. As it is known in the art, a buckconverter is suitable for dynamic DC to DC voltage conversion. Thevarious converted voltages may then be distributed into the power supplywiring of the IC, which power supply wiring may be part of themultilevel wiring network of the IC. For such a DC to DC voltageconverter to be useful it should be able to supply the various voltagesat an adequate current level.

So far in the art inductors that were able to fulfill their roles inswitched-inductor converters for ICs have been too bulky for integrationdirectly into the IC chip. Various ways around such problems have beendevised, such as stacking several chips, using interposers, and more.

A detailed analysis regarding the needs and figure of merits ofinductors has been recently given by N. Sturcken et al., “Design ofCoupled Power Inductors with Crossed Anisotropy Magnetic Core forIntegrated Power Conversion”, IEEE-APEC 2012, pp. 417-423, doi:10.1109/APEC.2012.6165853, which is incorporated herein by reference inits entirety.

Embodiments of the present invention teach inductor structures and theirmethods of fabrication, which inductor structures have the energystorage capability needed for modern DC to DC voltage converters, whiletheir size and shape is such that these inductors are fully integrableinto the multilevel wiring network, the BEOL, of individual VLSIsemiconductor ICs.

Inductors in representative embodiments of the present disclosure arebased on a planar magnetic core with a conductive winding, whichconductive winding turns around the outside of the planar magnetic corein a generally spiral manner.

FIG. 1 shows a schematic view of a planar magnetic core inductor 10 withwindings on its outside. The magnetic core 11 is a planar structurehaving, and defining, a principal plane 20. The planar magnetic core 11may typically be of a rectangular shape. The conductive winding 12 ofthe inductor is made to spiral around the outside of the planar core 11.The spiral of conductive winding 12 extends along a coil axis 32. Theconductive winding 12 has leads 13 that may connect to the winding inany desirable manner without limitation. The planar magnetic core 11includes a magnetic material, which can include any of the magneticmaterials described herein. Core 11 can be the same as or substantiallythe same as any of the cores described herein, including cores 51 and1611.

The direction 30 of a magnetic field that is induced when an electricalcurrent is flowing in the conductive winding 12 is substantially in theprincipal plane 20 directed substantially along the winding spiral, andpointing in a direction that depends on the direction of the current inthe winding. As it is known in the art, many magnetic materials areanisotropic, and possess so called hard and soft (or easy) axes ofmagnetization. The planar magnetic core 11 in representative embodimentsof the invention is fabricated to have its hard-axis 31 of magnetizationaligned substantially in parallel with the magnetic field 30 that isinduced when an electrical current is flowing in the conductive windings12. In addition or in the alternative, the planar magnetic core 11 inrepresentative embodiments of the invention is fabricated to have itshard-axis 31 of magnetization aligned substantially in parallel with itscoil axis 32. One or both of these alignments for the material of themagnetic core 11 is desirable because along the hard-axis the coremagnetization exhibits less hysteresis and has a substantially lineardependence on the current in the winding 12, resulting in more energyefficient operation of the inductor.

FIG. 2A shows schematic top view of a plurality of inductors 100 ofplanar magnetic cores with end couplings, and with windings according toan embodiment of the disclosure. The figure shows four magnetic cores 11in parallel, each capable for being used in an individual inductor, withplanar couplers 111 at each of their ends. The planar magnetic cores 11and the planar couplers 111 are arranged in the principal plane 20 ofthe magnetic cores, in the manner of a ladder. As a ladder has rungs andstringers, each of the planar magnetic cores 11 corresponds to one ofthe rungs of the ladder, and each of the planar couplers 111 correspondsto one of the stringers of the ladder. The conductive windings 12 eachare made to spiral around the outside of each of the plurality of planarcores 11. FIGS. 1 and 2A are only schematic, and though the parts of thecontinuous windings underneath the core are not even visible,nonetheless they indicate that the conductive winding 12 may spiralaround the magnetic core 11 in many differing ways. Any and all possiblemanner of winding around the outside of the magnetic core 11 is withinthe scope of the embodiments of the disclosure.

The number of planar magnetic cores 11 in FIG. 2A is 4. Typically theplurality of inductors 100 in the coupled cores configuration that isshown in FIG. 2A, may range between 2 and 20, but more typically between2 and 8. The advantages of the magnetic couplers 111 and the optimalmanner in what phases are the various magnetic cores 11 driven by thecurrent in the windings 12 is detailed by N. Sturcken et al., “Design ofCoupled Power Inductors with Crossed Anisotropy Magnetic Core forIntegrated Power Conversion”, IEEE-APEC 2012, pp. 417-423, doi:10.1109/APEC.2012.6165853. FIG. 2A shows that the leads 13 of thewindings 12 are all shorted 13′ together at one side, and areindependent on the other side of the inductors. Such a physicalarrangement may be advantageous when the multi-core coupled inductor 100is used in a DC to DC voltage converter. However, the displayedarrangement of the windings is meant to be understood as an example, andnot in a restrictive manner.

FIG. 2B shows schematic top view of a plurality of planar magnetic coresdefining structural dimensions. The vertical dashed lines in the figureare present only to guide the eye to distinguish between the magneticcores 11 and magnetic couplers 111. As before, the stringer/rungterminology will be used as convenient description of the structure.Five parameters may be used to characterize the planar coupled coremagnetic structure; length of a core: L_(rung) 121, width of a core:W_(rung) 122, separation of cores S_(rung) 123, width of a couplerW_(stringer) 124, and thickness of the magnetic layer, T_(core) 125which is only symbolically indicated since it is perpendicular to theplane displayed in FIG. 2B.

As a way of example, and without intent of limiting, finite elementnumerical simulations have been carried out for the particular case ofL_(rung)=270 μm, W_(rung)=120 μm, S_(rung)=50 μm, W_(stringer)=140 μm,T_(core)=5 μm, and assuming the planar magnetic cores and couplerscontain a Co/Zr/Ta (CZT) magnetic material in a laminated configuration.According to the simulation the four coupled inductors are capable ofdelivering a current density of 11 A/mm². With variations on corematerials the inductor may maintain its current density to at least 800MHz. The total area of the simulated core is 0.35 mm², a size that iseminently suitable to integrate into the BEOL of a semiconductor IC. Thearrangement of the planar cores and their coupling together with theoutside windings scheme allow the kind of energy density performancewhich makes such inductors small enough to integrate into the BEOL ofVLSI ICs, while delivering the necessary currents needed for theoperation of the ICs at the desired voltage levels.

General trends to find optimal parameter values for the coupled magneticcores may depend on the following. Increasing W_(rung) will reduce thereluctance for magnetic flux in the core at the expense of windinglength, which would increase DC resistance. S_(rung) is desired to be assmall as possible in order to maximize coupling between adjacent cores.However, this space must be large enough to accommodate the windingwhich will be placed between the rungs. Reducing L_(rung) reduces themagnetic path length and increases inductance at the expense of windingwire cross section, which increases DC resistance of the winding.Increasing W_(stringer) helps to improve coupling between cores, butwith diminishing effect, while it consumes more total area and hencereduces current density.

FIG. 2B also indicates that it may be advantageous, and inrepresentative embodiments of the disclosure it may be done so, to formthe planar magnetic cores 11 and the planar couplers 111 with the samechemical composition. In this manner the planar magnetic cores 11 andthe planar couplers 111 are becoming differing portions of a singleplanar structure, as the one depicted in FIG. 2B.

Embodiment of the present invention may depend on a coupled multi-coreplanar inductor design with windings on the outside of the cores. Suchan inductor design affords high efficiency even at sufficiently highcurrent densities that the inductor can be made small enough to offerthe possibility of full integration into a semiconductor IC wiringnetwork. The proper planar shape of the cores further aids with theintegration. Any and all optimizations and final dimensions of such aninductor design are within the scope of the embodiments of the instantdisclosure.

FIGS. 3A-3D show schematic cross-sectional views of planar magnetic coreinductors integrated into multilevel wiring networks according tovarious embodiments of the disclosure. FIG. 3A is a schematiccross-sectional view of the integration 200 of an inductor into themultilevel wiring network, or back end of the line (BEOL), of asemiconductor IC. The figure shows symbolically represented circuitcomponents 230, such as CMOS devices, have been processed on asemiconductor substrate 220. The devices may be any kind, planar orthree dimensional FinFET type, and the substrate, as well, any kind,bulk, SOI, Si based, or some other semiconductor based, withoutlimitation. Pertaining to the same die, and over the semiconductorsubstrate 220 and the components 230, a multilevel wiring network 240has been fabricated. In some embodiments, the inductor and at least aportion of the multilevel wiring network 240 for a transformer, a powerconverter, and/or a microprocessor.

The multilevel wiring network 240 is arranged into wiring planes 242.FIG. 3A depicts 5 wiring planes 242 but without limitation on any actualnumber of planes. Each wiring plane 242 contains wire segments 245.Electrical connections between wiring segments 245 of differing wiringplanes 242 are provided by VIAs 244. Also shown are typical IC chipcontact structures 243, usually referred to in the art as C4 contacts,but any other contacts for the chip's external communication areacceptable without limitation. The spaces in the wiring network 240 aretypically filled with a dielectric insulating material 249, of whichquite a few are known in the art, one of them may be SiO₂.

The schematic depiction of FIG. 3A show an inductor with a single planarmagnetic core 11 integrated 200 into the multilevel wiring network 240.The principal plane 20 of the planar magnetic core 11 is substantiallyparallel with the wiring planes 242. The conductive winding of theinductor, forming a general spiral on the outside of the planar magneticcore 11 is piecewise constructed of wire segments 245 and of VIAs 244.The wire segments 245 forming the winding pertain to at least two of thewiring planes 242′ and the VIAs 244′ that form the parts of the windingsthat are vertical to the principal plane 20 are interconnecting the atleast two wiring planes 242′. The wire segment underneath the planarmagnetic core 11 is delineated with dashed lines indicating that,depending how the winding spirals are constructed, it may not be visiblein the depicted cross-sectional plane. A possible lead 13 to thewindings is also shown.

Considering the discussion with reference to FIG. 2B, where in the shownexample the 4 core planar magnetic inductor was only 0.35 mm², and thata semiconductor IC die is typically several square millimeters, thefitting of the inductors in the embodiments of the instant inventioninto the planes of a wiring network poses no difficulty.

In state of the art semiconductor ICs the multilevel wiring network 240typically uses Cu for wire segments and VIAs, and it is fabricated witha dual damascene technique, as known in the art. Since the planarmagnetic core 11 is manufacturable with usual semiconductor processingmethods, for instance, sputtering, or electroplating, its integrationmay be seamlessly included into the BEOL processing.

FIG. 3B is a schematic cross-sectional view of the integration 200 of aninductor into the multilevel wiring network, or BEOL, of a semiconductorIC in a variant embodiment. The difference compared to FIG. 3A is thatFIG. 3B shows a wiring network with more planes, 7, and not only 2, butin the depicted case 4, wiring planes 242′ are contributing wiringsegments for the windings of the planar core 11. Such arrangements maybe useful for some inductor applications, and pose no difficulty for theBEOL processing to achieve.

FIG. 3C is a schematic cross-sectional view of the integration 200 of amulti-core inductor into the multilevel wiring network, or BEOL, of asemiconductor IC. Considering the discussions and notations in referenceto FIGS. 3A and 3B that carry over to FIG. 3C, only a brief explanationis given here. An integration of a three-core planar magnetic core 11inductor between two wiring planes 242′ is shown as another embodimentof the instant disclosure. The magnetic coupler 111 is indicated betweendashed lines because obviously it would not be visible in the presentedcross-sectional view.

FIG. 3D is a schematic cross-sectional view of the integration 201 of amulti-core inductor into the wiring planes of a multilevel wiringnetwork. The inductor may be integrated into the wiring planes 242, 242′of a multilevel wiring network 250 when that wiring network does notpertain to a semiconductor IC. If the need arises, the inductor in theembodiments of the instant invention may be integrated in a wiringnetwork of some sort chip auxiliary to a semiconductor IC. Suchauxiliary chip may be an interposer, between a power supply and asemiconductor IC. Or, maybe a power supply chip delivering power throughcontacts to a semiconductor IC. Such auxiliary chip may also be a chipcontaining some components for an analog circuit. Any and all suchstructures and their applications are within the scope of theembodiments of the present invention, where the inductor is integratedinto the wiring planes 242, 242′ of a multilevel wiring network 250.Here too, the integration of a three-core planar magnetic core 11inductor between two wiring planes 242′ with magnetic coupler 111outside plane of the figure is shown. Such multilevel wiring network 250arranged into wiring planes may be supported by any and all type ofsubstrates, or it may be completely free standing by itself. Because ofthe possibility of so many variations no one particular substrate isshown in the figure. FIG. 3D shows C4 contacts, but these are optional,as well.

FIGS. 4A-4C show schematic cross-sectional views of steps in theintegration of a planar magnetic core into a multilevel wiring networksaccording to an embodiment of the disclosure. Considering the planarconfiguration of the magnetic cores and couplers and that the winding isapplied on the outside of the cores, there are several possible ways tointegrate the inductor into a multilevel wiring network. The term“integration” is used throughout herein with its customary meaning ofbringing together, incorporate into a whole, to be part of the whole,etc.

As already stated earlier, multilevel wiring networks for state of theart semiconductor ICs typically are fabricated by a dual damasceneprocess. This process is well known in the art therefore it will not bediscussed here in detail. The dual damascene process is particularlysuitable for the integration of the planar magnetic cores and couplers.For representative embodiments of the disclosure the planar magneticcores and couplers are integrated into the BEOL as part of a dualdamascene process. FIGS. 4A-4C depict by way of an example theintegration of one core into the multilevel wiring network of asemiconductor IC. Integration of multi-cores with couplers would followin obvious manner from the process of the depicted example of a singlecore integration.

FIG. 4A shows the stage when the double damascene processing of themultilevel wiring network reached a point of having a planarizedsurface, with wiring segments of the last the wiring plane 242′ stillexposed at the top. The next step in a standard dual damascene processwould be to deposit a layer of the insulating material 249 over the lastwiring plane of sufficient thickness to accommodate the height of theVIAs that will connect to the next higher wiring level. For the case ofintegrating a magnetic core into the multilevel wiring network of theinstant invention, one also deposits a layer of the insulating material249′ as shown in FIG. 4B, but one that is only a portion of the eventualfull thickness. The magnetic core 11 is then fabricated on the top ofthis partial thickness insulator layer 249′ to its proper location.FIGS. 4B-4C show only the top part of the multilevel wiring networkwhere the integration takes place. It is understood that the bottom partis unchanging and it is the same as that of FIG. 4A.

FIG. 4C shows the state of integration progressed further. After havingcompleted the fabrication of the magnetic core 11, the insulator layer249 with further deposition is completed to its needed thickness toaccommodate the VIAs. During this further deposition the core 11 isburied into this last layer of the insulator. Next, following now againthe standard double damascene processing VIA holes 244′ are patternedinto the last layer of the insulator. Amongst the many VIA holes at thislevel, there are those 244′ that will be filled with VIAs that will bepart of the inductor's winding, as shown in FIG. 4C. From here on, it isstandard double damascene processing, VIA filling next, followed byfurther levels, and so on, finally with contacts such as C4s. Havingperformed these steps, one arrives at the structure depicted in FIG. 3A:the completed BEOL with the planar magnetic core 11 having beenintegrated. It is understood that the insulator level that contains theplanar magnetic core 11 is made of the right thickness to have thewinding-made up of wire segments and VIAs-with the desired separationfrom the core.

FIGS. 4A-4C have shown, by way of example, integration of the inductorinto the steps of a dual damascene process. It is understood that theplanar structure of the core and the outside the core winding schemeallows integration of into the processing steps of practically any BEOLtechnique, such as single damascene, electroplating, and others.

FIG. 5 symbolically depicts a processor with a device that uses a planarmagnetic core inductor according to an embodiment of the disclosure. Theterm processor is used in the broadest sense; encompassing any kind ofcomputing device, including, but not limited to mainframes,supercomputers, servers, personal computers, mobile devices, hand-helddevices, battery powered computer devices, imbedded processors, andothers. The processor 300, includes a semiconductor integrated circuit270. The semiconductor integrated circuit 270 operates with a pluralityof DC supply voltages. The plurality of such DC supply voltages mayrange between 2 to 10. The processor 300 has a DC to DC voltageconverter 260, which delivers at least one of the DC supply voltages forthe semiconductor integrated circuit 270. The whole of the DC to DCvoltage converter 260 may, or may not, be fully integrated into thesemiconductor integrated circuit 270, but an inductor 170 that is partof the DC to DC voltage converter 260 is fully integrated into themultilevel wiring network of the semiconductor integrated circuit 270.The circle symbolizing the DC to DC converter 260 in FIG. 5 would implythat the whole of the DC to DC converter 260 is not integrated into thesemiconductor integrated circuit 270, but this is for example only norfor limitation.

The inductor 170 includes a planar magnetic core and a conductivewinding, with the conductive winding turning around in generally spiralmanner on the outside of the planar magnetic core. The multilevel wiringnetwork may be arranged into wiring planes that are parallel with aprincipal plane of the planar magnetic core. The conductive winding maybe piecewise constructed of wire segments and of VIAs, in a manner thatthe wire segments pertain to at least two of the wiring planes and theVIAs are interconnecting the at least two wiring planes. The planarmagnetic core of the inductor 170 may have multiple cores coupled toeach other in a ladder like manner.

FIG. 6 is a cross-sectional view of the laminated composition of planarmagnetic core 11 according to an embodiment of the disclosure. Thelaminated configuration includes at least one layer of a magneticmaterial 410 and at least one non-magnetic layer 420. The purpose of thenon-magnetic layer 420 is to prevent electrical current circulation inthe planar magnetic core perpendicularly to the principal plane 20,which principal plane is parallel with the lamination layers. In atypical embodiment of the disclosure the magnetic core 11 may contain analternating sequence of up to 100 layers each, more typically between 2to 50 periods of the layers. FIG. 6 shows 3 periods of the layers, 3magnetic ones 410 and 3 non-magnetic ones 420.

By way of example, without intent of limiting, the magnetic layer 410may be of CZT, or Co_(x)Zr_(y)Ta_(1-x-y), with x and y beingapproximately 0.915 and 0.04, respectively. In addition or in thealternative, the magnetic layer 410 can comprise a ferromagnetic alloyas described below (e.g., with respect to magnetic layer 710). Thenon-magnetic layer 420 itself may be composed of more than oneconstituent layers. Again, by way of example, these component layers maybe an insulator layer 421, such as SiO₂ or Co_(x)O_(y) (e.g., CoO), anda metal layer 422, such as Ta, Al, Cr, Ti and/or Zr. The purpose of theinsulating layer 421 is to prevent electrical current circulation in theplanar magnetic core perpendicularly to the principal plane 20. Suchperpendicular currents are known in the art as Eddy currents, and theywould lead to energy losses for the inductor. The purpose of the metallayer 422, such as Ta, may be to ease fabrication by smoothing thesurface during deposition. The non-magnetic layer 420 may havestructures and properties beyond those of simply having constituentlayers. In some embodiments of the present invention the non-magneticlayer 420 may have current rectifying properties.

The sequential deposition of the various layers of the laminatedstructure may include some techniques known in the semiconductorprocessing arts, for instance, masking, sputtering, electroplating. Thefabrication of the laminated magnetic cores may be done in the presenceof an applied magnetic field to control the anisotropy and coercivity ofthe deposited magnetic layers 410 (or any other magnetic layer describedherein). This applied magnetic field induces anisotropy of the depositedmagnetic layers 410 which decreases their coercivity and thereby reducespower loss of the magnetic layers in the magnetic core 11. Theorientation of the applied magnetic field may be parallel to the surfaceof the laminated magnetic core 11 (e.g., parallel to the principal plane20 of the core 11). The applied magnetic field induces an “easy axis” ofmagnetization that aligns with the applied magnetic field, with the“hard axis” of magnetization assuming an orientation that is alsoparallel to the surface of the laminated magnetic core 11, andperpendicular to the “easy axis” of magnetization. The “hard axis” ofmagnetization exhibits a linear response, low coercivity, and highpermeability, which are desirable for inductance enhancement. Therefore,the orientation of the applied magnetic field for inducing magneticanisotropy is chosen with respect to inductor coil orientation so thatthe “hard axis” (e.g., hard axis 31) of magnetization is predominately(e.g., at least partially) aligned with the inductor coil axis (e.g.,coil axis 32). For example, the hard axis of magnetization can besubstantially parallel to (or at least partially aligned with) theinductor coil axis. In a specific example, the hard axis ofmagnetization and the inductor coil axis can be parallel to each otheror the axes can intersect one another and form less than or equal to a30° angle, including a 25° angle, a 20° angle, a 15° angle, a 10° angle,a 5° angle, or any angle or angle range between any two or theforegoing. Consequently, magnetic fields that are generated when anelectrical current passes through the inductor coil are predominatelyaligned with the “hard axis,” such that the inductor achieves linearresponse, low hysteretic loss, and large inductance enhancement.

The applied magnetic field may originate from either a permanent magnetand/or an electromagnet apparatus near the deposition substrate and thisfield is greater than any other magnetic fields originating from themagnet array(s) associated with magnetron sputtering or relatedapparatus as measured at the surface of the depositionsubstrate/deposited magnetic layer. The applied magnetic fieldoriginating from the permanent magnet and/or electromagnet apparatus maynot quantifiably change the magnetic field originating from the magnetarray(s) associated with magnetron sputtering or related apparatus. Thepermanent magnetic and/or the electromagnet apparatus can be in closeproximity, preferably less than 1 mm and no more than 5 mm from thesurface of the deposition substrate/deposited magnetic layer, such thatthe magnetic field originating from the permanent magnetic and/or theelectromagnet apparatus is concentrated at the surface of the depositionsubstrate. The permanent magnet and/or electromagnet apparatus may becomprised either partially or entirely of the ferromagnetic materialsiron, cobalt or nickel or some combination or alloy of any of thesematerials. The applied magnetic field strength may be in the range ofabout 20 Oe to about 20,000 Oe. As used herein, “about” means plus orminus 10% of the relevant value.

In a similar manner, magnetic anisotropy may be induced in the magneticfilm after it is deposited by applying an external magnetic fieldranging from about 20 Oe to about 20,000 Oe for a duration of about 30minutes or more with the magnetic film at an elevated temperatureranging from about 200° C. to about 400° C. In such a “post deposition”magnetic anneal, the “easy axis” of magnetization will again assume thesame orientation of the applied magnetic field.

Examples of methods of inducing magnetic anisotropy in a laminatedmagnetic core, including during deposition and post-deposition, arefurther described in U.S. Patent Application Publication 2015/0371756,U.S. Pat. No. 9,647,053, and/or U.S. Pat. No. 9,337,251, which arehereby incorporated by reference.

The thickness of the non-magnetic layers 420 may be in the range ofabout 5 nm to 100 nm, while the magnetic layer thickness 410 may be of10 nm to 1000 nm, more typically between 50 nm to 500 nm. Of course, onemay be able to apply other magnetic materials, such as Ni and Fe, andother layers, or means, to suppress Eddy currents. Embodiments of thepresent invention do not limit any of these choices.

Considering the nature of its materials and its structural requirements,representative embodiments of the invention may use differing generalapproaches for fabricating the planar laminated magnetic cores andcouplers. A general approach may be centered on sputtering, anotherapproach on electroplating.

FIG. 7 is a cross-sectional view of the laminated composition of planarmagnetic core 11 according to another embodiment of the disclosure. Themagnetic core 11 lies in a principal plane 770, which is parallel to thex-y plane as illustrated. The laminated configuration includes analternating sequence of a magnetic layer 710 and a non-magnetic layer720. The non-magnetic layer 720 includes an insulating layer 724disposed between first and second interface layers 722, 726. The firstand second interface layers 722, 726 are disposed adjacent to (e.g., indirect physical contact with) a respective magnetic layer 710. Forexample, in FIG. 7 the first interface layer 722 is disposed on a“lower” magnetic layer 710 and the second interface layer 726 isdisposed below an “upper” magnetic layer 710. Of course, the magneticcore 11 illustrated in FIG. 7 can be disposed in other orientationswhere the relative terms “lower” and “upper” may not apply, but thelayers would maintain the same relative positions with respect to eachother.

A capping layer 730 is disposed on the last (or first or final) magneticlayer 711 on a first side 750 of the magnetic core 11, which is disposedfurther away from the substrate (e.g., semiconductor substrate 220) thana second side 760 of the magnetic core 11. An adhesion layer 740 isdisposed below the last (or first or final) magnetic layer 712 on thesecond side 760 of the magnetic core 11. In FIG. 7, the first side 750corresponds to the “top” side of the magnetic core 11 and the secondside 760 corresponds to the “bottom” side of the magnetic core 11. Asdiscussed above, the magnetic core 11 illustrated in FIG. 7 can bedisposed in other orientations where the relative terms “top” and“bottom” may not apply, but the layers and sides would maintain the samerelative positions with respect to each other.

The magnetic layers 710-712 can comprise the same materials as orsubstantially the same materials as magnetic layer 410. For example,magnetic layers 710-712 can comprise or can consist only of (oressentially of) CZT, e.g., Co_(x)Zr_(y)Ta_(1-x-y), with x and y beingapproximately 0.915 and 0.04, respectively. In another example, themagnetic layers 710-712 can comprise or can consist only of (oressentially of) CoZrTa—B (or CoZrTaB), CoNiFe, NiFe, and/or CoFeB, oralloys that include any of the foregoing compounds. In yet anotherexample, the magnetic layers 710-712 can comprise or can consist only of(or essentially of) a ferromagnetic alloy having an iron (Fe)composition of about 10 atomic % to about 90 atomic %, including about20 atomic %, 30 atomic %, 40 atomic %, 50 atomic %, 60 atomic %, 70atomic %, 80 atomic %, and any value or range between any two of theforegoing atomic compositions. In other words, about 10% to about 90% ofthe atoms in the ferromagnetic alloy are iron atoms. Examples of such aferromagnetic alloy include CoFeB, CoFe, and combinations thereof. Theatomic percentage of iron can provide a saturation magnetization of atleast 1.5 T for the ferromagnetic alloy (and thus for magnetic layers710-712), which can be useful to achieve a high saturation current forthin-film integrated power inductors. For example, an increase in thesaturation magnetization (e.g., a 25% increase in saturationmagnetization, such as from 1.2 T to 1.5 T) can provide a proportionalor approximately equal increase (e.g., about 25%) in inductor saturationcurrent. In addition or in the alternative, the atomic percentage ofiron in the ferromagnetic alloy can provide a coercivity of less than orequal to 1.0 Oe, which can be useful to achieve low power loss when themagnetic layers 710-712 are exposed to an alternating magnetic field.For example, a coercivity of less than or equal to 1.0 Oe can achieve apower loss of less than 10 mW in a representative 5 nH inductor (e.g.,in an inductor that includes magnetic layers 710-712 that comprise aferromagnetic alloy having an atomic iron composition of about 10 atomic% to about 90 atomic %, as discussed above) driven by a 200 MHz ACcurrent stimulus of 1 A in amplitude.

In some embodiments, the ferromagnetic alloy can include one or moreferromagnetic materials other than iron, such as cobalt or nickel, whichcan balance magnetostriction. For example, the materials can be combined(e.g., one or more materials or elements can have a positivemagnetostriction value and/or a positive magnetostriction coefficientand one or more materials or elements can have a negativemagnetostriction value and/or a negative magnetostriction coefficient)so that the ferromagnetic alloy has approximately a net 0magnetostriction. In addition or in the alternative, the ferromagneticalloy can include one or more non-magnetic elements such as boron,tantalum, chromium, cobalt, titanium, or zirconium to increase theelectrical resistivity of the material. For example, incorporating boroninto CoZrTa can increase the electrical resistivity of the material byabout 15% (e.g., from about 100 μΩ to about 115 μΩ) while maintainingthe same or similar (e.g., within about 10%) magnetic properties of thematerial.

The materials that form magnetic layers 710-712 can be anisotropicmagnetic materials and/or can be manufactured as (e.g., induced tobecome) anisotropic magnetic materials that have hard and easy axes ofmagnetization that are permanent or semi-permanent. In some embodiments,the materials that form magnetic layers 710-712 can have an easy axis ofmagnetization that is parallel to the “x” axis and a hard axis ofmagnetization that is parallel to the “y” axis, as illustrated in FIG.7, such that the hard axis of magnetization is substantially in parallelwith the magnetic field 30.

The interface layers 722, 726 can comprise a metal such as tantalum,aluminum, chromium, cobalt, titanium, and/or zirconium. In addition orin the alternative, the interface layers 722, 726 can comprise asemiconducting material such as silicon. The capping layer 730 and theadhesion layer 740 can comprise any of the materials (e.g., metalsand/or semiconducting materials) discussed above with respect tointerface layers 722, 726. In some embodiments, the interface layers722, 726, the capping layer 730, and/or the adhesion layer 740 comprisethe same material(s). In addition, the interface layers 722, 726, thecapping layer 730, and/or the adhesion layer 740 can have the samethickness or height. The thickness or height of each layer can bemeasured with respect to an axis that extends orthogonally from thefirst side 750 to the second side 760 of the magnetic core 11. Forexample, the interface layers 722, 726, the capping layer 730, and/orthe adhesion layer 740 have a thickness or height of about 1 angstrom toabout 500 angstroms, including about 100 angstroms, about 200 angstroms,about 300 angstroms, about 400 angstroms, and/or any value or rangebetween any two of the foregoing thicknesses or heights.

The interface layers 722, 726, the capping layer 730, and/or theadhesion layer 740 can reduce the magnetic coercivity of the magneticlayers 710-712 to thereby reduce power loss in the magnetic core 11 whenit is exposed to an alternating magnetic field. For example theinterface layers 722, 726, the capping layer 730, and/or the adhesionlayer 740 can (1) reduce roughness (e.g., to a root mean squaredroughness of less than or equal to 20 angstroms) at the interfacebetween the magnetic layers 710-712 and the non-magnetic layer 720because roughness at this interface layer increases the coercivity ofthe magnetic layers 710-712; (2) prevent or inhibit diffusion of oxygenand/or nitrogen from the insulating layer 724 into the magnetic layers710-712 (e.g., the corresponding neighboring magnetic layer(s)) becausesuch diffusion allows for the formation of other defects and materialcompounds that can increase the magnetic coercivity of the magneticlayers 710-712; or (3) getter (e.g., have an affinity for, to react withfor the formation of material compounds) trace impurities such as oxygenand/or nitrogen in the magnetic layers 710-712, that may be incorporatedunintentionally through the fabrication process, that may increase themagnetic coercivity of the magnetic layers 710-712. In a specificexample, the inclusion of the interface layers 722, 726 can reduce themagnetic coercivity of the magnetic layers 710-712 in the magnetic core11 by greater than 0.1 Oe relative to a magnetic core that does notinclude interface layers 722, 726.

The insulating layer 724 can comprise a compound of the material(s) thatcomprise(s) the interface layers 722, 726 and oxygen and/or nitrogen.For example, the insulating layer 724 can comprise a compound of (a) oneor more metals that form the interface layers 722, 726 (e.g., tantalum,aluminum, chromium, cobalt, titanium, and/or zirconium) and (b) oxygenand/or nitrogen. In a specific example, the interface layers 722, 726can comprise tantalum, aluminum, chromium, cobalt, and/or titanium andthe insulating layer 724 can comprise, respectively, (a) tantalumnitride (Ta_(x)N_(y) such as TaN) and/or tantalum oxide (Ta_(x)O_(y)such as Ta₂O₅), (b) aluminum nitride (Al_(x)N_(y) such as AlN) and/oraluminum oxide (Al_(x)O_(y) such as Al₂O₃), (c) chromium oxide(Cr_(x)O_(y) such as CrO or Cr₂O₃), (d) cobalt oxide (Co_(x)O_(y) suchas CoO, Co₂O₃, or Co₃O₄), and/or (e) titanium dioxide (Ti_(x)O_(y) suchas TiO, TiO₂, or Ti₂O₃), where the atomic composition of (x) tantalum,aluminum, and/or titanium and (y) nitrogen and/or oxygen (i.e. the ratioof Ta, Al, Cr, Co, and/or Ti atoms to O and/or N atoms) in the depositedmaterial can be the energetically-favorable composition as determined bythe deposition method (e.g., reactive sputtering) for fabrication of theinterface layers 722, 726 and insulating layer 724.

In another example, the insulating layer 724 can comprise a compound ofone or more semiconductor materials that form the interface layers 722,726 (e.g., silicon) and oxygen and/or nitrogen. In a specific example,the interface layers 722, 726 can comprise silicon and the insulatinglayer 724 can comprise silicon nitride (Si_(x)N_(y) such as SiN orSi₃N₄) and/or silicon oxide (Si_(x)O_(y) such as SiO₂).

The insulating layer 724 has a volume or bulk resistivity of at least1,000 μΩ-cm to block or minimize eddy currents that would form in thecore 11 in the presence of an alternating magnetic field. The thicknessor height of the insulating layer 724 can be measured with respect to anaxis that extends orthogonally from the first side 750 to the secondside 760 of the magnetic core 11. For example, the thickness or heightof the insulating layer 724 can be about 10 angstroms to about 1,000angstroms, including about 100 angstroms, about 200 angstroms, about 300angstroms, about 400 angstroms, about 500 angstroms, about 600angstroms, about 700 angstroms, about 800 angstroms, about 900angstroms, and/or any value or range between any two of the foregoingthicknesses or heights. In some embodiments, the insulating layer 724has a root mean squared roughness of less than or equal to 20 angstroms,which can reduce the coercivity of the adjacent magnetic layer (e.g.,magnetic layer 710, 711, or 712) deposited above the insulating layer724.

The sequential deposition of the various layers of the laminatedstructure may include some techniques known in the semiconductorprocessing arts, for instance, masking, sputtering, electroplating. Thefabrication of the laminated magnetic cores may be done in the presenceof an applied magnetic field to align the easy axis of magnetization ofthe deposited magnetic layers 710-712. This applied magnetic fieldaligns (or at least partially aligns) the easy axis of magnetization(i.e. induces anisotropy) of the deposited magnetic layers with theapplied magnetic field and the hard axis of magnetization with the coilorientation on the wafer which decreases the coercivity of the magneticlayers and thereby reduces power loss of the magnetic layers in themagnetic core. The orientation of the applied magnetic field may beparallel to the surface of the laminated magnetic core. The appliedmagnetic field may originate from either a permanent magnet and/or anelectromagnet apparatus near the deposition substrate and the appliedmagnetic field is greater than any other magnetic fields originatingfrom the magnet array(s) associated with magnetron sputtering or relatedapparatus as measured at the surface of the depositionsubstrate/deposited magnetic layer. The applied magnetic fieldoriginating from the permanent magnet and/or electromagnet apparatus maynot quantifiably change the magnetic field originating from the magnetarray(s) associated with magnetron sputtering or related apparatus. Theapplied magnetic field may be generated in close proximity, preferablyless than 1 mm and no more than 5 mm. from the surface of the depositionsubstrate/deposited magnetic layer. In some embodiments, the appliedmagnetic field can be generated from a permanent magnetic film that isdisposed beneath the substrate (e.g., on the wafer chuck) in themagnetic material deposition chamber. The permanent magnet and/orelectromagnet apparatus may be comprised either partially or entirely ofthe ferromagnetic materials iron, cobalt or nickel or some combinationor alloy of any of these materials. The applied magnetic field strengthmay be in the range of 20 Oe to 20,000 Oe.

In addition or in the alternative, the laminated magnetic core 11 may besubjected to an external magnetic field, after the layers of core 11 aredeposited in a “post deposition” magnetic anneal, under controlledprocessing conditions for temperature and time to permanently orsemi-permanently align (or at least partially align) the easy axis ofmagnetization with the external magnetic field and the hard axis ofmagnetization with the coil orientation on the wafer. For example, theexternal magnetic field can be applied for a duration of about 30minutes or more with the magnetic film at an elevated temperatureranging from about 200° C. to about 400° C. The orientation of thisexternal magnetic field may be parallel to the surface of the laminatedmagnetic core 11 (e.g., parallel to principal plane 20). The externalmagnetic field strength may be in the range of 20 Oe to 20,000 Oe.

Additional details of inducing magnetic anisotropy in a laminatedmagnetic core are described herein and in the patents and patentpublications that are incorporated by reference, including U.S. PatentApplication Publication 2015/0371756, U.S. Pat. No. 9,647,053, and/orU.S. Pat. No. 9,337,251.

Considering the nature of its materials and its structural requirements,representative embodiments of the invention may use differing generalapproaches for fabricating the planar laminated magnetic cores andcouplers. A general approach may be centered on sputtering, anotherapproach on electroplating.

FIG. 8A illustrates a flow chart 80A of a method for sputter depositingthe non-magnetic layers 720 of a planar magnetic core (e.g., core 11)according to an embodiment of the disclosure. In step 800, thesemiconductor wafer or substrate is placed in a physical vapordeposition (PVD) chamber and high vacuum (HV) sputtering is started. Instep 810, the first interface layer 722 is deposited via HV sputteringof an interface material that includes one or more metals and/orsemiconductor materials, as discussed above. In step 820, a stream ofgas (e.g., O₂ and/or N₂) that can react with the HV sputtered metal(s)and/or semiconductor material(s) is introduced into the PVD chamber.

In step 830, the insulating layer 724 is deposited via reactivesputtering where the gas the HV sputtered material form a molecularcompound. For example, if the first interface layer is formed oftantalum and the gas stream includes nitrogen, reactive sputtering formsa tantalum nitride film as the insulating layer 724. Additional examplesand combinations of interface layer materials and gasses are discussedabove.

In step 840, the gas stream is stopped as the HV sputtering continues.As the remainder of the gas in the PVD chamber is consumed or depleted(i.e., via reactive sputtering), the second interface layer 726 isdeposited in step 850. Once the second interface layer 726 is deposited,HV sputtering is stopped in step 860.

Since the same PVD chamber is used for steps 810 and 850 (in addition tothe other steps in flow chart 80A), the first and second interfacelayers 722, 726 are formed out of the same material(s) and theinsulating layer 724 is a compound (e.g., including nitrogen and/oroxygen) of the material(s) that form the first and second interfacelayers 722, 726. In addition, the use of the same PVD chamber for eachstep in flow chart 80A minimizes the total time required for depositionof non-magnetic layers 720.

FIG. 8B illustrates a flow chart 80B for a method of manufacturing aninductor according to an embodiment of the disclosure. In step 8000, amagnetic material is deposited over a semiconductor substrate (e.g., onan insulating layer) that includes at least a portion of a multilevelwiring network to form a magnetic layer (e.g., a first magnetic layer).The magnetic material can be any of the magnetic materials describedherein, including the ferromagnetic alloy described above with respectto magnetic layers 710-712. The insulating layer can be disposed on oneof the wiring planes of at least a portion of a multilevel wiringnetwork, such as multilevel wiring network 240. In step 8010, anon-magnetic layer is deposited on the magnetic layer formed in step8000. In some embodiments, step 8010 is performed according to flowchart 80A. In other embodiments, the non-magnetic layer is or comprisesan electrically insulating layer (e.g., SiO₂), which can be deposited asknown in the art. In step 8020, steps 8000 and 8010 are repeated up to100 times each to form an alternating sequence of magnetic layers(formed in step 8000) and non-magnetic layers (formed in step 8010).

After step 8020 is complete, the flow chart 80B proceeds to step 8030where a magnetic material is deposited on the last non-magnetic layer inthe alternating sequence of magnetic layers and non-magnetic layers toform a final magnetic layer. The magnetic material that forms the finalmagnetic layer in step 8030 can be the same magnetic material that formsthe magnetic layer in step 8000. The resulting structure following step8030 is a magnetic member with a laminated configuration.

In some embodiments, the magnetic material deposited in steps 8000(including repeating step 8000 in step 8020) and/or in step 8030 isdeposited in the presence of an external or bias magnetic field of about20 Oe to about 20,000 Oe to induce magnetic anisotropy in thecorresponding magnetic layer, as described herein. The external magneticfield can induce an easy axis of magnetization in parallel with theexternal magnetic field as it passes through the substrate and a hardaxis of magnetization that is orthogonal to the easy axis ofmagnetization. In addition, the external magnetic field can beconfigured so that the hard axis of magnetization is induced to be atleast partially aligned with the axis of the conductive winding (formedin step 8050).

In some embodiments, the external or bias magnetic field can begenerated by a permanent magnetic film that is disposed underneath thesubstrate. For example, the permanent magnetic film can be disposed on awafer chuck in the magnetic film deposition chamber (e.g., in a PVD orCVD chamber) and the wafer/substrate can be placed on the permanentmagnetic film. The permanent magnetic film can directly contact theunderside of the wafer/substrate or a surface of the permanent magneticfilm can be separated by about 1 mm to about 5 mm from a surface of thesubstrate/wafer.

In some embodiments, a permanent magnet can be positioned or placedproximal to the location where the substrate/wafer is deposited withmagnetic material, such as proximal to the wafer chuck in the magneticfilm deposition chamber. For example, a surface of the permanent magnetcan be disposed about 1 mm to about 5 mm from a surface of thesubstrate/wafer when the substrate/wafer is disposed on the wafer chuck(or other location where the substrate/wafer is deposited with magneticmaterial).

Alternatively, the substrate/wafer can be exposed to an externalmagnetic field (e.g., of about 20 Oe to about 20,000 Oe) after themagnetic member with a laminated configuration is formed (e.g.,following step 8030 or any step thereafter). While the substrate/waferis exposed to the external magnetic field, the substrate/wafer is heatedto about 200° C. to about 400° C. for at least 30 minutes. After theheating is complete, each magnetic layer in the magnetic member isinduced to be permanently and/or semi-permanently anisotropic. Forexample, the hard axis of magnetization in each magnetic layer can beinduced to be at least partially aligned with the axis of the conductivewinding (formed in step 8050).

In step 8040, the magnetic member is masked and patterned to form aplanar magnetic core. The masking and patterning can proceed asdescribed herein and/or as known in the art. In step 8050, a conductivewinding is formed around the planar magnetic core. The conductivewinding can be piecewise constructed of wire segments and of VIAs asdescribed herein.

In optional step 8060, a non-magnetic material is deposited below thefirst magnetic layer (i.e., formed in step 8000 prior to the repeatingstep 8020) and/or on the final magnetic layer formed in 8030. Thenon-magnetic material includes tantalum, aluminum, chromium, cobalt,titanium, zirconium, and/or a semiconductor material such as silicon.When the metal layer is deposited below the first magnetic layer, anadhesion layer, such as adhesion layer 740, is formed on the firstmagnetic layer. When the metal layer is deposited on the final magneticlayer, a capping layer, such as capping layer 730, is formed on thefinal magnetic layer.

FIGS. 9A-9B show schematic views of embodiments for fabricatinglaminated planar magnetic cores and couplers by sputtering. In general,HV sputtering is preferred. The approaches one may take differ dependingon whether it is possible to etch the magnetic material and thenon-magnetic layer with the same etchant. If there is no known commonetchant, for instance, as in the case when the magnetic material is CZTand the non-magnetic layer comprises a SiO₂ layer, one may apply anegative masking resist and a liftoff process as known in the art. Onestage in this process is schematically illustrated in FIG. 9A.

The planar magnetic core is to be fabricated onto the surface of areceiving platform 510. Such a receiving platform in typical embodimentsof the instant invention would be the dielectric insulating material,249′ in FIG. 4B, in the multilevel wiring network of a semiconductor IC.A negative photoresist 511 has been disposed onto the receiving platform510 patterned and opened up, preferably with an undercut, as shown inFIG. 9A. The layers of a magnetic material and the non-magnetic layerare alternatively disposed by sputtering 521, up to 100 layers each, butmore typically between 2 to 50 layers each. The layers of the magneticmaterial may be 10 nm to 1000 nm thick, but more typically between 50 nmto 500 nm thick. The result is a magnetic member with a laminatedconfiguration 550. After dissolving the masking material 511, whichlifts off the unwanted portions of the magnetic member 550, theremaining portion of the magnetic member on the surface of the receivingplatform 510 is of the proper shape to contain a planar magnetic core.

When all the layers of the laminated magnetic cores and couplers areetchable in the same process one may use HV sputtering with a positivephotoresist, a stage of which is shown in FIG. 9B. The sputteringdeposition and parameters of the layers of a magnetic material mayproceed as discussed with reference to FIG. 9A. An insulating layer ofthe non-magnetic layer may be an oxide of Co, Ni, or Fe. Alternatively,the sputtering of the magnetic material may continue uninterrupted, butwhen an insulating layer is needed one introduces reactive oxygensputter deposition and the insulating layer will be formed by an oxideof the magnetic material itself, such as CZT. In this embodiment, themagnetic member 550 is blanket formed over the receiving platform 510.When the sputtering deposition is finished, a masking layer is depositedand patterned 512 over the magnetic member. Next an etching step 531 isperformed, which may be a wet etch or a dry etch. With the unwantedportions of the magnetic member 550 etched away, the remaining portionof the magnetic member on the surface of the receiving platform 510 isof the proper shape to contain a planar magnetic core. For the specificcase of CZT magnetic layers with CoO insulating layers, a viable wetetchant may be based on hydrogen chloride (HCl) and/or nitric acid(HNO₃), while a dry etch process may use a plasma formed from a chlorineand/or fluorine gas.

In both approaches shown in FIGS. 9A and 9B respectively, the maskingand patterning for the magnetic member is done in such a manner that aremaining portion of the magnetic member 550 includes a planar magneticcore, or a plurality of cores and possibly magnetic couplers.

Electroplating is an alternative process for fabricating the laminatedmagnetic cores and couplers. The advantage of electroplating is itssimplicity coupled with being relatively inexpensive. The difficultywith the electroplating is that the current required for the platingshould be able to flow through the already deposited material.Consequently, the insulating layers of the laminated material would stopthe electrodeposition process by blocking the current needed for thedeposition. Embodiment of the instant disclosure find the way aroundthis problem by electrodepositing such non-magnetic layers that arerectifying, instead of being insulators. Current rectifying layers arealso suitable to suppress Eddy currents in the core, since in order forEddy currents to circulate they would have to cross the currentrectifying layers from both direction, which the rectifying layers wouldprevent. On the other hand, if the direction of the plating current ischosen correctly, it may flow through the current rectifying layers.

Rectification may be included in the non-magnetic layers, for instance,based on Schottky diodes. Onto the magnetic material layer, one mayelectrodeposit the following sequence: a semiconducting layer-p-typewith work function less than magnetic layer or n-type with work functiongreater than magnetic layer—; followed by an interface metal layer—witha work function less than that of p-type semiconducting material, orgreater than that of n-type semiconducting material. Then, continue withthe next magnetic material layer, and so on.

Alternatively, for rectification one may use a semiconductor p-njunction in the non-magnetic layer. Any semiconductor may be suitable,one would have to choose one based on several criteria, for examplewithout limiting, the ease of contact to the magnetic material of the pand n portions, how narrow can one make the junction, and others.

FIG. 10 shows a schematic view of fabricating laminated planar magneticcores and couplers by electroplating. The nature of the non-magneticlayers is as discussed above, and will not be repeated here. Same aswith sputtering deposition, embodiments the planar magnetic core is tobe fabricated onto the surface of a receiving platform 510. Such areceiving platform in typical embodiments of the instant invention wouldbe the dielectric insulating material, 249′ in FIG. 4B, in themultilevel wiring network of a semiconductor IC. Onto the receivingplatform 510 one may deposit a conductive seed layer 542, for instanceAl, Cu, or a magnetic alloy, such as, for instance, Ni_(x)Fe_(1-x) withx being approximately 0.45 to 0.80. A masking layer 513 is depositedover the conductive seed 542, and patterned to have an opening with theproper shape for cores and couplers. Next, the layers of a magneticmaterial and the non-magnetic layer are alternatively electrodepositedfrom the plating solution 555. Such electroplating solutions are knownin the art. The electrodeposition may proceed for 100 layers each, butmore typically between 2 to 50 layers each. The layers of the magneticmaterial may be 10 nm to 1000 nm thick, but more typically between 50 nmto 500 nm thick. All the while the conductive seed layer 542 completes apath 541 for the electrodeposition current. The layers, of course, willonly deposit into the opening in the masking material since the maskingmaterial is an insulator. When the required number of layers have beendeposited the masking layer 513 is removed and portion of the conductiveseed layer 542 is exposed. Once the exposed portion of the conductiveseed layer is removed, a planar magnetic formation 551 with a laminatedconfiguration is left in place. Because of the masking 513 this magneticformation 551 already includes at least one planar magnetic core, andpossibly a plurality of cores, with couplers.

All of these various depositions processes are devised to serve a methodwhich is characterized as fabricating a planar inductor suitable forintegrating into a multilevel wiring network that is arranged intowiring planes.

FIG. 11 is a cross-sectional view of planar magnetic core 11 in whichthe thicknesses of the magnetic and non-magnetic layers are co-optimizedfor layer-to-layer magnetic flux closure, according to an embodiment ofthe disclosure. In FIG. 11, the core 11 includes an alternating sequence1125 of magnetic layers 1110- and non-magnetic layers 1120. Magneticlayers 1110 can be the same as or substantially the same as magneticlayers 410 and/or 710-712. In addition, non-magnetic layers 1120 can bethe same as or substantially the same as non-magnetic layer 420 and/or720. As in magnetic layers 710-712, the materials that form magneticlayers 1110 can be anisotropic magnetic materials and/or canmanufactured as (e.g., induced to become) anisotropic magnetic materialsthat have hard and easy (or soft) axes of magnetization that arepermanent or semi-permanent. In some embodiments, the materials thatform magnetic layers 1110 can have an easy axis of magnetization that isparallel to the “x” axis and a hard axis of magnetization that isparallel to the “z” axis, as illustrated in FIG. 11, such that the hardaxis of magnetization is substantially in parallel with the magneticfield 30.

The thicknesses or heights (in general, thicknesses) of magnetic layers1110 and non-magnetic layers 1120 are co-optimized for layer-to-layermagnetic flux closure, as indicated by magnetic flux lines 1100 inmagnetic layers 1110-1113. To promote layer-to-layer magnetic fluxclosure, the thicknesses of magnetic layers 1110 and non-magnetic layers1120 can be selected so that the magnetization energy for thelayer-to-layer flux closure state is lower than the magnetization energyfor the “in-layer” flux closure state, which can cause formation ofmagnetic domain walls. In addition, the thickness of magnetic layers1110 can be selected so that the magnetic flux lines 1100 passingthrough the magnetic layers 1110 are parallel to and/or substantiallyparallel to (e.g., within 10 degrees) to the easy axes of magnetizationof magnetic layers 1110.

In some embodiments, magnetic layers 1110 have a thickness of about 100angstroms to about 10,000 angstroms, including about 1,000 angstroms,about 2,000 angstroms, about 3,000 angstroms, about 4,000 angstroms,about 5,000 angstroms, about 6,000 angstroms, about 7,000 angstroms,about 8,000 angstroms, about 9,000 angstroms, and/or any value or rangebetween any two of the foregoing thicknesses. In addition or in thealternative, non-magnetic layers 1120 have a thickness of about 10angstroms to about 2,000 angstroms, including about 500 angstroms, about1,000 angstroms, about 1,500 angstroms, and/or any value or rangebetween any two of the foregoing thicknesses. The thicknesses ofmagnetic layers 1110 and non-magnetic layers 1120 can be measured withrespect to the “z” axis, which is orthogonal to the principal plane 1170of the core 11. The principal plane 1170 of the core 11 is parallel tothe x-y plane as illustrated in FIG. 11.

It is noted that even when layer-to-layer flux closure occurs, it isstill common to have some magnetic domain walls present within magneticlayers 1110. However, the number of domain walls is reduced relative tothe case where magnetic flux is primarily closed within an individualmagnetic layer. When layer-to-layer flux closure occurs, there are fewerdomain walls present in each individual magnetic layer 1110 in themagnetic core 11. This is advantageous because (1) domain walls can movewhen the core is exposed to an alternating magnetic field which causespower loss and (2) domain patterns that form when magnetic flux isclosed within individual magnetic layers can reduce the total volume ofmagnetic material that respond to alternating magnetic fields,consequently reducing the maximum achievable inductance.

An optional capping layer 1130 is disposed on (e.g., in direct physicalcontact with) a final magnetic layer 1111 on a first side 1150 of themagnetic core 11, which is disposed further away from the substrate(e.g., semiconductor substrate 220) than a second side 1160 of themagnetic core 11. The final magnetic layer 1111 is disposed on a lastnon-magnetic layer 1121 in the alternating sequence 1125 of magneticlayers 1110 and non-magnetic layers 1120. An optional adhesion layer1140 is disposed immediately below (e.g., in direct physical contactwith) the first magnetic layer 1112 on the second side 1160 of themagnetic core 11. The first magnetic layer 1112 is the first magneticlayer 1110 in the alternating sequence 1125 of magnetic layers 1110 andnon-magnetic layers 1120. The capping layer 1130 and/or the adhesionlayer 1140 can be the same as or substantially the same as the cappinglayer 730 and the adhesion layer 740, respectively. In addition, thelast and first magnetic layers 1111, 1112, respectively, can be the sameas magnetic layers 1110. Further the last non-magnetic layer 1121 can bethe same as non-magnetic layers 1120. The last non-magnetic layer 1121is disposed on (e.g., in direct physical contact with) the last magneticlayer 1113. The last magnetic layer 1113 is the last magnetic layer 1110in the alternating sequence 1125 of magnetic layers 1110 andnon-magnetic layers 1120. The last non-magnetic layer 1121 1113 is thelast non-magnetic layer 1120 in the alternating sequence 1125 ofmagnetic layers 1110 and non-magnetic layers 1120.

FIG. 12 is an exploded perspective view of the top surface 1150 of theplanar magnetic core 11 illustrated in FIG. 11. FIG. 12 furtherillustrates the magnetic flux lines 1100 as they pass in a firstdirection (i.e., from right-to-left in FIG. 12) through the finalmagnetic layer 1111 and in a second direction (i.e., from left-to-right)through the neighboring magnetic layer 1110. The magnetic flux lines1100 that pass through the final magnetic layer 1111 extend to theneighboring magnetic layer 1110 as indicated by magnetic flux lines1101. Likewise, the magnetic flux lines 1100 that pass through theneighboring magnetic layer 1110 extend to the final magnetic layer 1111as indicated by magnetic flux lines 1102. Accordingly, the magnetic fluxhas a closed path through the final magnetic layer 1111 and theneighboring magnetic layer 1110. The magnetic flux lines 1100 areparallel or substantially parallel to (i.e., within 10 degrees) to theeasy axis of magnetization and orthogonal to or substantially orthogonalto (i.e., within 10 degrees) the hard axis of magnetization whenmagnetic flux lines 1100 pass through the magnetic layers 1110, 1111.

FIG. 12 also illustrates magnetic flux lines 1103 that pass through theneighboring magnetic layer 1110 in a second magnetic flux closed paththat extends through the magnetic layer (not illustrated) adjacent to(below) the neighboring magnetic layer 1110. The second magnetic fluxclosed path is parallel to the easy axis of magnetization and orthogonalto the hard axis of magnetization. The optional capping layer 1130 andthe optional adhesion layer 1140 are not illustrated in FIG. 12 forclarity.

FIG. 13 is a cross-sectional view of planar magnetic core 11 that isfurther co-optimized for layer-to-layer magnetic flux closure, accordingto another embodiment of the disclosure. In FIG. 13, layer-to-layermagnetic flux closure is further optimized by using a similar unitthickness “UT” for all magnetic layers 1110 in the core 11 except forthe final magnetic layer 1311 on the first side 1150 of the magneticcore 11 and the first magnetic layer 1112 on the second side 1160 of themagnetic core 11. The respective final and first magnetic layers 1311,1312 are the same as the final and first magnetic layers 1111, 1112,respectively except their thickness is half of UT (i.e., UT/2). In otherwords, the magnetic layers 1110 are twice as thick as (or twice the unitthickness of) the final and first magnetic layers 1311, 1312,respectively. The final and first magnetic layers 1311, 1312 are half asthick as the other magnetic layers 1110 because they only need to closehalf of the magnetic flux 1100 from the adjacent magnetic layers 1313,1314, respectively. The other half of the magnetic flux 1100 from theadjacent magnetic layers 1313, 1314 is closed by the adjacent magneticlayers 1110 on the opposite side of magnetic layers 1313, 1314. Forexample, the other half of the magnetic flux 1100 from magnetic layer1313 is closed by magnetic layer 1315. This configuration reduces theenergy associated with flux closure outside of the core 11 by reducingthe magnetic flux closure path length.

The planar core 11 illustrated in FIG. 13 is otherwise the same as theplanar core 11 illustrated in FIGS. 11 and 12.

FIG. 14 is a cross-sectional view of planar magnetic core 11 that isfurther configured for layer-to-layer magnetic flux closure, accordingto another embodiment of the disclosure. In FIG. 14, orthogonalnon-magnetic layers 1420, 1422 and orthogonal magnetic layers 1410, 1412are disposed along the lateral sides of core 11 (i.e., next to the core11 in the “x” direction as illustrated in FIG. 14). The orthogonalnon-magnetic layers 1420, 1422 and orthogonal magnetic layers 1410, 1412extend vertically (i.e., in the “z” direction as illustrated in FIG. 14)from the first side 1150 to the second side 1160 of the core 11. Theorthogonal non-magnetic layers 1420, 1422 and orthogonal magnetic layers1410, 1412 are orthogonal to the laminations of magnetic layers 1110 andnon-magnetic layers 1120 (e.g., they are orthogonal to the sequence 1125of magnetic layers 1110 and non-magnetic layers 1120 illustrated inFIGS. 11-13) and to the principal plane 1170 of the core 11. Magneticlayer 1410 is disposed in a hole 1450 between first and second portions1420A, 1420B of non-magnetic layer 1420. Magnetic layer 1412 is disposedin a hole 1452 between first and second portions 1422A, 1422B ofnon-magnetic layer 1422. The magnetic layers 1410, 1412 are configuredand arranged such that each closed magnetic flux path passes through aportion of the orthogonal magnetic layers 1410, 1412 as illustrated bymagnetic flux lines 1400. Accordingly, each closed magnetic flux pathpasses through two or more magnetic layers 1110 and through a portion ofthe orthogonal magnetic layers 1410, 1412, as illustrated by magneticflux lines 1100, 1400.

Arrows 1401 illustrate an example of a magnetic flux path 1402 thatpasses through the final magnetic layer 1111, orthogonal magnetic layer1412, magnetic layer 1110, and orthogonal magnetic layer 1410. Themagnetic flux path 1402 is parallel to the “x” axis, but in oppositedirections, in magnetic layers 1111 and 1110. The magnetic flux path1402 extends in orthogonal directions, parallel to the “z” axis, inorthogonal magnetic layers 1412, 1410. The magnetic flux path 1402 is inthe negative “z” direction (e.g., down) in orthogonal magnetic layer1412 and it is in the positive “z” direction (e.g., up) in orthogonalmagnetic layer 1410. Thus, the magnetic flux path 1402 passes inopposite directions in magnetic layers 1110 and 1112, and in oppositedirections in orthogonal magnetic layers 1410 and 1412.

The orthogonal magnetic layer(s) 1410 and/or 1412 can comprise the samematerial(s) as magnetic layers 1110. In addition or in the alternative,the orthogonal non-magnetic layers 1420 and/or 1422 can comprise thesame material(s) as non-magnetic layers 1120. In some embodiments, theorthogonal magnetic layer(s) 1410 and/or 1412 can include anisotropicmagnetic materials and/or can include materials that are manufactured as(e.g., induced to become) anisotropic magnetic materials that have hardand easy (or soft) axes of magnetization that are permanent orsemi-permanent (e.g., as described herein). In some embodiments, thematerials that form orthogonal magnetic layer(s) 1410 and/or 1412 havean easy axis of magnetization that is parallel to the “z” axis so thatthe magnetic flux lines 1400 (e.g., magnetic flux path 1402) that passthrough the orthogonal magnetic layers 1410 and 1412 are parallel toand/or substantially parallel to (i.e., within 10 degrees) the easy axisof magnetization of orthogonal magnetic layer(s) 1410 and/or 1412.Likewise, the materials that form magnetic layer(s) 1110 and/or 1111 canhave an easy axis of magnetization that is parallel to the “x” axis sothat the magnetic flux lines 1100 (e.g., magnetic flux path 1402) thatpass through the magnetic layers 1110 and 1111 are parallel to and/orsubstantially parallel to (i.e., within 10 degrees) the easy axis ofmagnetization of magnetic layer(s) 1110 and/or 1111.

It is noted that non-idealities in the manufacturing process, such aswet-etch undercut, can result in sloped “sidewalls” (i.e., the lateralsides of the core 11 that are disposed adjacent portions 1420B and 1422Aof non-magnetic layers 1420, 1422) for the core 11 that may cause the“orthogonal” magnetic layers 1410 and/or 1412 to reside in a plane thatis not entirely parallel to the z-axis, but rather, in-plane with thecorresponding sloped sidewall.

The heights of the orthogonal magnetic layers 1410, 1412 and thenon-magnetic layers 1420, 1422 can be measured with respect to the “z”axis, which is orthogonal to the principal plane 1170 of the core 11.Likewise, the thickness or height of the core 11 can be measured withrespect to the “z” axis. In some embodiments, the height(s) of theorthogonal magnetic layers 1410 and/or 1412 is equal to or approximatelyequal to (i.e., within 10%) the height of the core 11. In addition or inthe alternative, the height(s) of the non-magnetic layers 1420 and/or1422 can be equal to or approximately equal to (i.e., within 10%) theheight of the core 11. In other embodiments, height(s) of any or all ofthe orthogonal magnetic layers 1410, 1412 and/or non-magnetic layers1420, 1422 can be greater than the height of the core 11.

The planar core 11 illustrated in FIG. 14 is otherwise the same as theplanar core 11 illustrated in FIGS. 11 and 12.

FIG. 15 is a cross-sectional view of planar magnetic core 51 that isfurther configured for layer-to-layer magnetic flux closure, accordingto another embodiment of the disclosure. Core 51 includes a combinationof the features illustrated in FIGS. 11-14 to further promotelayer-to-layer magnetic flux closure. Thus, core 51 includes magneticlayers 1110 having the same or similar thickness of UT and final andfirst magnetic layers 1111, 1112, respectively, having a thickness ofUT/2, as described above with respect to FIG. 13. In addition, core 560includes orthogonal non-magnetic layers 1420, 1422 and orthogonalmagnetic layers 1410, 1412 that are disposed along the sides (orsidewalls) of core 51, as described above with respect to FIG. 14. Insome embodiments, orthogonal magnetic layers 1410, 1412 can have across-sectional thickness 1500 (i.e., measured with respect to the “x”axis) of UT or UT/2.

FIG. 16 is a cross-sectional view of an inductor 1600 and first andsecond magnetic flux closure layers 1620, 1622 according to one or moreembodiments. The inductor 1600 includes a planar core 1611 and aconductive winding 1612 that spirals around the outside of the planarcore 1611. The core 1611 and conductive winding 1612 can be the same asor similar to any of the cores (e.g., core 11) and conductive windings(e.g., conductive winding 12) described herein.

First and second magnetic flux closure layers 1620, 1622 aremagnetically coupled to the inductor 1600. The magnetic flux closurelayers 1620, 1622 are formed of a magnetic material that can comprisethe same material(s) as magnetic layers 1110. In addition, the magneticmaterials that form the magnetic flux closure layers 1620, 1622 can beanisotropic magnetic materials and/or can manufactured as (e.g., inducedto become) anisotropic magnetic materials that have hard and easy axesof magnetization that are permanent or semi-permanent. In someembodiments, the hard axis of magnetization of the magnetic flux closurelayers 1620, 1622 is parallel to the “x” axis such that AC magnetic flux1630 from the inductor 1600 passes through each magnetic flux closurelayer 1620, 1622 in a direction that is parallel to (i.e., in the samedirection or in the opposite direction as) the respective hard axis ofmagnetization of the magnetic flux closure layer 1620, 1622.

The first and second magnetic flux closure layers 1620, 1622 are not indirect physical contact with the core 1611 such that first and secondgaps 1640, 1642 across dielectric insulating material 1649 are formedbetween the core 1611 and the first and second magnetic flux closurelayers 1620, 1622, respectively. The size of the gaps 1640, 1642 can beadjusted to control the total magnetic reluctance along the inductormagnetic flux path. For example, a smaller gap distance (and/or largergap cross-sectional area) can lower magnetic reluctance and canconsequently increase inductance for the inductor 1600. In someembodiments, each gap 1640, 1642 is 100 μm or less, such that thedistance between the first and second magnetic flux closure layers 1620,1622 and the first and second sides 1650, 1660, respectively, of thecore 1611 is 100 μm or less including about 30 μm, about 40 μm, about 50μm, about 60 μm, about 70 μm, about 80 μm, about 90 μm, and any value orrange between any two of the foregoing distances. In other embodiments,only one of the gaps 1640, 1642 is 100 μm or less. The distance betweenthe first magnetic flux closure layer 1620 and the first side 1650 ofthe core 1611 is measured with respect to the “inner” surface of eachlayer 1620, 1650 that face each other (e.g., from the “bottom” of fluxclosure layer 1620 to the “top” of the first side 1650). Likewise, thedistance between the second magnetic flux closure layer 1622 and thesecond side 1660 of the core 1611 is measured with respect to the“inner” surface of each layer 1622, 1660 that face each other (e.g.,from the “top” of flux closure layer 1622 to the “bottom” of the secondside 1660). The first side 1650 of the magnetic core 1611 is disposedfurther away from the substrate (e.g., semiconductor substrate 220) thanthe second side 1660 of the magnetic core 1611.

In addition or in the alternative, the length (measured with respect tothe “x” axis) of each magnetic layer 1620 and 1622 and the core 1611extends at least 20 μm beyond the conductive winding 1612 to reducefringing of magnetic flux in the conductive winding 1612 interconnect(i.e., so the magnetic flux doesn't pass through the winding 1612 whichcan induce larger eddy current losses). FIG. 16 also illustrates thatthe length of the magnetic layers 1620, 1622 extend beyond (e.g., atleast 20 μm beyond) the core 1611.

The first and second magnetic flux closure layers 1620, 1622 aredisposed outside of the core 1611, for example above and below theconductive winding 1612. In some embodiments, the second magnetic fluxclosure layer 1622 is disposed between the conductive winding 1612 andany lower interconnect and/or semiconductor layers 1710 in theintegrated circuit 1700 (as illustrated in FIG. 17) in order to providea low magnetic reluctance path for closing the inductor magnetic fluxsuch that the magnetic flux does not pass through the lower interconnectand/or semiconductor layers.

The first and second magnetic flux closure layers 1620, 1622 function asflux closure layers for the inductor 1600 as indicated by magnetic fluxlines 1630. In other words, at least one magnetic flux path passesthrough a first magnetic layer (e.g., which can be the same as finalmagnetic layer 1111 in core 11) in the core 1611 and the first magneticflux closure layer 1620, and/or at least one magnetic flux path passesthrough a second magnetic layer (e.g., which can be the same as firstmagnetic layer 1112 in core 11) in the core 1611 and the second magneticflux closure layer 1622. Closing the magnetic flux path of the first andsecond magnetic flux closure layers 1620, 1622 can increase theinductance and power handling of inductor 1600 and can decrease theradiated magnetic flux from the inductor 1600. In some embodiments, afirst magnetic flux path 1631 passes through a first magnetic layer(e.g., which can be the same as final magnetic layer 1111 in core 11) inthe core 1611 and the first magnetic flux closure layer 1620 in adirection that is parallel to the hard axis of magnetization of thefirst magnetic layer in the core 1611 and in a direction that isparallel to the hard axis of magnetization of the first magnetic fluxclosure layer 1620. In addition or in the alternative, a second magneticflux path 1632 passes through a second magnetic layer (e.g., which canbe the same as first magnetic layer 1112 in core 11) in the core 1611and the second magnetic flux closure layer 1622 in a direction that isparallel to the hard axis of magnetization of the second magnetic layerin the core 1611 and in a direction that is parallel to the hard axis ofmagnetization of the second magnetic flux closure layer 1622.

The combined thickness of the first and second magnetic flux closurelayers 1620, 1622 can be less than the total thickness of the core 1611to control the magnetic permeability of the core 1611 by engineering thecombination of process-induced anisotropy and shape-induced anisotropythereby promoting flux closure. In addition, the thickness of eachmagnetic flux closure layer 1620, 1622 can be equal to, approximatelyequal to, or less than the thickness of one or more or all of themagnetic layers in the core 1611 to achieve similar eddy current lossesat a given frequency even with higher magnetic permeability. Each of theforegoing thicknesses is measured with respect to the “z” axis or withrespect to a respective reference axis that is parallel to the “z” axis.The “z” axis and the respective reference axes are orthogonal to theprincipal plane 1670 of the core 1611.

At least one of the dimensions of the in the “x” and/or “y” directions(e.g., the length and/or width, respectively) of each magnetic fluxclosure layer 1620, 1622 can be greater than the correspondingdimension(s) of the core 1611. For example, in FIG. 16 the length ofeach magnetic flux closure layer 1620, 1622 along the “x” dimension isgreater than the length of the core 1611 along the “x” dimension. Inother embodiments, the width of each magnetic flux closure layer 1620,1622 along the “y” dimension is greater than the width of the core 1611along the “y” dimension. In yet other embodiments, the length and widthof each magnetic flux closure layer 1620, 1622 are greater than thelength and width of the core 1611. In other embodiments, the length ofthe first magnetic flux closure layer 1620 is greater than the length ofthe core 1611 and the width of the second magnetic flux closure layer1622 is greater than the width of the core 1611. In yet otherembodiments, the width of the first magnetic flux closure layer 1620 isgreater than the width of the core 1611 and the length of the secondmagnetic flux closure layer 1622 is greater than the length of the core1611. In other embodiments, the length and/or width of the firstmagnetic flux closure layer 1620 is greater than the length and/or widthof the core 1611 and the length and width of the second magnetic fluxclosure layer 1622 is less than or equal to the length and/or width ofthe core 1611. In yet other embodiments, the length and/or width of thesecond magnetic flux closure layer 1622 is greater than the lengthand/or width of the core 1611 and the length and width of the firstmagnetic flux closure layer 1620 is less than or equal to the lengthand/or width of the core 1611.

It is noted that although FIGS. 16 and 17 illustrate two magnetic fluxclosure layers 1620, 1622, in other embodiments only one magnetic fluxclosure layer 1620 or 1622 is present. In such embodiments, onlymagnetic flux closure layer 1620 or 1622 is magnetically coupled to theinductor 1600. In one example, when only the first magnetic flux closurelayer 1620 is present, the first magnetic flux closure layer 1620 isdisposed within about 100 μm from the first side 1650 of the core 1611,the first side 1650 of the core 1611 being further away from thesubstrate (e.g., semiconductor substrate 220) than the second side 1660of the core 1611. In another example, when only the second magnetic fluxclosure layer 1622 is present, the second magnetic flux closure layer1622 is disposed within about 100 μm from the second side 1660 of thecore 1611, the second side 1660 of the core 1611 being closer to thesubstrate (e.g., semiconductor substrate 220) than the first side 1650of the core 1611.

FIG. 18 illustrates a flow chart 18000 for a method of manufacturing aninductor according to an embodiment of the disclosure. In step 18001, amagnetic material is deposited over a semiconductor substrate (e.g., onan insulating layer) that includes at least a portion of a multilevelwiring network to form a magnetic layer (e.g., a first magnetic layer).The insulating layer can be disposed on one of the wiring planes of atleast a portion of a multilevel wiring network, such as multilevelwiring network 240.

The magnetic material includes a ferromagnetic alloy, such as theferromagnetic alloy described above with respect to magnetic layers710-712, that has a composition of about 10 atomic percent to about 90atomic percent iron. The magnetic material can also include at least oneadditional ferromagnetic material that does not include iron, such ascobalt and/or nickel. In addition or in the alternative, the magneticmaterial can also include boron, tantalum, chromium, cobalt, titanium,zirconium, or a combination of two or more of the foregoing. Themagnetic material can be anisotropic, and/or can be induced to bepermanently and/or semi-permanently anisotropic, such that its hard axisof magnetization is at least partially aligned with an axis of theconductive winding, the conductive winding extending along the axis.

In step 18010, a non-magnetic layer is deposited on the magnetic layerformed in step 18001. In some embodiments, step 18010 is performedaccording to flow chart 80A. In other embodiments, the non-magneticlayer comprises a current-rectifying layer, as described herein. Thecurrent-rectifying layer can comprise a p-type semiconductor having afirst work function less than a second work function of the magneticmaterial and/or an n-type semiconductor, the n-type semiconductor havinga first work function greater than a second work function of themagnetic material

In step 18020, steps 18001 and 18010 are repeated up to 100 times eachto form an alternating sequence of magnetic layers (formed in step18001) and non-magnetic layers (formed in step 18010).

After step 18020 is complete, the flow chart 80B proceeds to step 18030where a magnetic material is deposited on the last non-magnetic layer inthe alternating sequence of magnetic layers and non-magnetic layers toform a final magnetic layer. The magnetic material that forms the finalmagnetic layer in step 18030 can be the same magnetic material thatforms the magnetic layer in step 18001. The resulting structurefollowing step 18030 is a magnetic member with a laminatedconfiguration.

In some embodiments, the magnetic material deposited in steps 18001(including repeating step 18001 in step 18020) and/or in step 18030 isdeposited in the presence of an external or bias magnetic field of about20 Oe to about 20,000 Oe to induce magnetic anisotropy in thecorresponding magnetic layer, as described herein. The external magneticfield can induce an easy axis of magnetization in parallel with theexternal magnetic field as it passes through the substrate and a hardaxis of magnetization that is orthogonal to the easy axis ofmagnetization. In addition, the external magnetic field can beconfigured so that the hard axis of magnetization is induced to be atleast partially aligned with the axis of the conductive winding (formedin step 18050).

In some embodiments, the external or bias magnetic field can begenerated by a permanent magnetic film that is disposed underneath thesubstrate. For example, the permanent magnetic film can be disposed on awafer chuck in the magnetic film deposition chamber (e.g., in a PVD orCVD chamber) and the wafer/substrate can be placed on the permanentmagnetic film. The permanent magnetic film can directly contact theunderside of the wafer/substrate or a surface of the permanent magneticfilm can be separated by about 1 mm to about 5 mm from a surface of thesubstrate/wafer.

In some embodiments, a permanent magnet can be positioned or placedproximal to the location where the substrate/wafer is deposited withmagnetic material, such as proximal to the wafer chuck in the magneticfilm deposition chamber. For example, a surface of the permanent magnetcan be disposed about 1 mm to about 5 mm from a surface of thesubstrate/wafer when the substrate/wafer is disposed on the wafer chuck(or other location where the substrate/wafer is deposited with magneticmaterial). Alternatively, the substrate/wafer can be exposed to anexternal magnetic field (e.g., of about 20 Oe to about 20,000 Oe) afterthe magnetic member with a laminated configuration is formed (e.g.,following step 18030 or any step thereafter).

While the substrate/wafer is exposed to the external magnetic field, thesubstrate/wafer is heated to about 200° C. to about 400° C. for at least30 minutes. After the heating is complete, each magnetic layer in themagnetic member is induced to be permanently and/or semi-permanentlyanisotropic. For example, the hard axis of magnetization in eachmagnetic layer can be induced to be at least partially aligned with theaxis of the conductive winding (formed in step 18050).

In step 18040, the magnetic member is masked and patterned to form aplanar magnetic core. The masking and patterning can proceed asdescribed herein and/or as known in the art. In step 18050, a conductivewinding is formed around the planar magnetic core. The conductivewinding can be piecewise constructed of wire segments and of VIAs asdescribed herein.

In optional step 18060, a non-magnetic material is deposited below thefirst magnetic layer (i.e., formed in step 18001 prior to the repeatingstep 18020) and/or on the final magnetic layer formed in 18030. Thenon-magnetic material includes tantalum, aluminum, chromium, cobalt,titanium, zirconium, and/or a semiconductor material such as silicon.When the metal layer is deposited below the first magnetic layer, anadhesion layer, such as adhesion layer 740, is formed on the firstmagnetic layer. When the metal layer is deposited on the final magneticlayer, a capping layer, such as capping layer 730, is formed on thefinal magnetic layer.

FIGS. 19 and 20 illustrate a flow chart 19000 for a method ofmanufacturing an inductor according to an embodiment of the disclosure.In step 19001, a magnetic material is deposited over a semiconductorsubstrate (e.g., on an insulating layer) that includes at least aportion of a multilevel wiring network to form a magnetic layer (e.g., afirst magnetic layer). The insulating layer can be disposed on one ofthe wiring planes of at least a portion of a multilevel wiring network,such as multilevel wiring network 240.

The magnetic material can include any of the magnetic materialsdescribed herein. In one example, the magnetic material includes aferromagnetic alloy, such as the ferromagnetic alloy described abovewith respect to magnetic layers 710-712, that has a composition of about10 atomic percent to about 90 atomic percent iron. In another example,the magnetic material can also include at least one additionalferromagnetic material that does not include iron, such as cobalt and/ornickel. In addition or in the alternative, the magnetic material canalso include boron, tantalum, chromium, cobalt, titanium, zirconium, ora combination of two or more of the foregoing. The magnetic material canbe anisotropic, and/or can be induced to be permanently and/orsemi-permanently anisotropic, such that its hard axis of magnetizationis at least partially aligned with an axis of the conductive winding,the conductive winding extending along the axis. The magnetic materialcan be deposited to have a thickness of about 100 angstroms to about10,000 angstroms. In some embodiments, the magnetic material isdeposited to form a magnetic layer that is the same as or similar tomagnetic layer 1110.

In step 19010, a non-magnetic layer is deposited on the magnetic layerformed in step 19001. In some embodiments, step 19010 is performedaccording to flow chart 80A. In other embodiments, the non-magneticlayer comprises an insulating material and/or a current-rectifyinglayer, as described herein. The non-magnetic layer can be deposited tohave a thickness of about 10 angstroms to about 2,000 angstroms. In someembodiments, the non-magnetic layer is the same as or similar tonon-magnetic layer 1120.

In step 19020, steps 19001 and 19010 are repeated up to 100 times eachto form an alternating sequence of magnetic layers (formed in step19001) and non-magnetic layers (formed in step 19010).

After step 19020 is complete, the flow chart 80B proceeds to step 19030where a magnetic material is deposited on the last non-magnetic layer inthe alternating sequence of magnetic layers and non-magnetic layers toform a final magnetic layer. The magnetic material that forms the finalmagnetic layer in step 19030 can be the same magnetic material and/orthe same thickness of magnetic material that forms the magnetic layer instep 19001. The resulting structure following step 19030 is a magneticmember with a laminated configuration.

In some embodiments, the first and final magnetic layers can have afirst thickness and the other magnetic layers in the alternatingsequence can have a second thickness, the first thickness being one halfof the second thickness, for example as illustrated in FIG. 13.

In some embodiments, the magnetic material deposited in steps 19001(including repeating step 19001 in step 19020) and/or in step 19030 isdeposited in the presence of an external or bias magnetic field of about20 Oe to about 20,000 Oe to induce magnetic anisotropy in thecorresponding magnetic layer, as described herein (e.g., as describedabove in flow chart 18000).

In step 19040, the magnetic member is masked and patterned to form aplanar magnetic core. The masking and patterning can proceed asdescribed herein and/or as known in the art.

In step 19050, a conductive winding is formed around the planar magneticcore. The conductive winding can be piecewise constructed of wiresegments and of VIAs as described herein.

In optional step 19060, a non-magnetic material is deposited below thefirst magnetic layer (i.e., formed in step 19001 prior to the repeatingstep 19020) and/or on the final magnetic layer formed in 19030. Thenon-magnetic material includes tantalum, aluminum, chromium, cobalt,titanium, zirconium, and/or a semiconductor material such as silicon.When the metal layer is deposited below the first magnetic layer, anadhesion layer, such as adhesion layer 740, is formed on the firstmagnetic layer. When the metal layer is deposited on the final magneticlayer, a capping layer, such as capping layer 730, is formed on thefinal magnetic layer.

The planar magnetic core that is formed from the method illustrated inflow chart 1900, which can include optional step 19060, can be the sameas or similar to planar magnetic core 11 illustrated in FIGS. 11-13.

In step 20000, a closed magnetic flux path is formed through neighboringmagnetic layers (e.g., through first and second magnetic layers). Themagnetic flux path can extend parallel to the easy axes of magnetizationin the neighboring magnetic layers. Additional details of the closedmagnetic flux path are described herein, for example with respect toFIGS. 11-15.

In step 20010, at least one orthogonal non-magnetic layer is disposedlaterally from the planar magnetic core, and in step 20020 a hole isdefined in each (or the) orthogonal non-magnetic layer to define firstand second portions of each (or the) orthogonal non-magnetic layer. Instep 20030, a respective orthogonal magnetic layer is deposited in thehole defined in the orthogonal non-magnetic layer(s).

In step 20040, a closed magnetic flux path is formed and extends throughneighboring magnetic layers in the planar magnetic core and through theorthogonal magnetic layer(s). The magnetic flux path is parallel to theeasy axis of magnetization of each magnetic layer (neighboring magneticlayers, such as first and second magnetic layers, in the planar magneticcore, and the orthogonal magnetic layer(s)).

Additional details of steps 20000-20040 and the structures formedtherefrom illustrated in and described above with respect to FIGS. 14and 15.

FIG. 21 illustrates a flow chart 21000 for a method of manufacturing aninductor according to an embodiment of the disclosure. In step 21010, aninductor is formed according to any of the flowcharts corresponding toFIG. 8B, FIG. 18, and/or FIGS. 19-20. In step 21020, a first magneticflux closure layer is formed within about 100 microns of a first face ofthe planar magnetic core (i.e., the planar magnetic core formedaccording to the corresponding flowchart in FIG. 8B, FIG. 18, and/orFIGS. 19-20). The face of the planar magnetic core is parallel to theprincipal plane of the planar magnetic core. The first magnetic fluxclosure layer is at least as long and/or at least as wide as the planarmagnetic core. The length and width are measured with respect tocorresponding axes that are parallel to the principal plane of theplanar magnetic core.

In some embodiments, a second magnetic flux closure layer is formedwithin about 100 microns of a second face of the planar magnetic core.The first and second faces of the planar magnetic core are on opposingfaces of the planar magnetic core, and they are parallel to theprincipal plane of the planar magnetic core.

The conductive winding can be disposed between the planar magnetic coreand the first magnetic flux closure layer. The conductive winding canalso be disposed between the planar magnetic core and the secondmagnetic flux closure layer.

Additional details of the magnetic flux closure layers are illustratedin and described above with respect to FIGS. 16 and 17.

Various inventive aspects of the technology are described below.

An aspect of the invention is directed to a structure comprising: asemiconductor integrated circuit comprising a multilevel wiring networkdisposed on a substrate; an inductor integrated into said multilevelwiring network, said inductor comprising a planar laminated magneticcore and a conductive winding that turns around in a generally spiralmanner on the outside of said planar laminated magnetic core, saidplanar laminated magnetic core comprising an alternating sequence of amagnetic layer and a non-magnetic layer; and a magnetic flux closurelayer disposed within about 100 μm of a face of the planar laminatedmagnetic core, the face of the planar magnetic core parallel to aprincipal plane of the planar laminated magnetic core.

In one or more embodiments, the conductive winding is disposed betweenthe planar laminated magnetic core and the magnetic flux closure layer.In one or more embodiments, the magnetic flux closure layer extendsacross a length and a width of the face of the planar laminated magneticcore, the length and the width measured with respect to the principalplane of the planar laminated magnetic core. In one or more embodiments,the magnetic flux closure layer extends beyond the length and the widthof the face of the planar laminated magnetic core. In one or moreembodiments, the face of the planar laminated magnetic core is furtheraway from the substrate than an opposing face of the planar laminatedmagnetic core. In one or more embodiments, the face of the planarlaminated magnetic core is closer to the substrate than an opposing faceof the planar laminated magnetic core.

In one or more embodiments, the face of the planar laminated magneticcore is closer to the substrate than the opposing face of the planarlaminated magnetic core; and wire segments in at least one wiring planein the multilevel wiring network are disposed between the inductor andthe substrate; the magnetic flux closure layer is disposed between theinductor and the wire segments in the at least one wiring plane. In oneor more embodiments, the magnetic flux closure layer provides a lowmagnetic reluctance path for an inductor magnetic flux. In one or moreembodiments, the magnetic flux closure layer prevents the inductormagnetic flux from passing through any wire segments in the at least onewiring plane.

In one or more embodiments, a thickness of the magnetic flux closurelayer is less than a total thickness of the planar laminated magneticcore, the thickness and the total thickness measured with respect to anaxis that is orthogonal to the principal plane of the planar laminatedmagnetic core. In one or more embodiments, a first thickness of themagnetic flux closure layer is less than or equal to a second thicknessof each magnetic layer, the first and second thicknesses measured withrespect to an axis that is orthogonal to the principal plane of theplanar laminated magnetic core. In one or more embodiments, the secondthickness of each magnetic layer is the same. In one or moreembodiments, the magnetic flux closure layer comprises the same materialas the magnetic layers.

In one or more embodiments, the planar laminated magnetic core and themagnetic flux closure layer are configured so that a magnetic fluxpasses through a first magnetic layer in the planar laminated magneticcore in a first direction that is parallel to a first hard axis ofmagnetization of the first magnetic layer and the magnetic flux passesthrough the magnetic flux closure layer in a second direction that isparallel to a second hard axis of magnetization of the magnetic fluxclosure layer. In one or more embodiments, each magnetic layer in theplanar laminated magnetic core comprises a first anisotropic magneticmaterial and the magnetic flux closure layer comprises a secondanisotropic magnetic material, the first and second anisotropic magneticmaterials having a respective hard axis of magnetization that is atleast partially aligned with an axis of the conductive winding, theconductive winding extending along the axis of the conductive winding.In one or more embodiments, the first anisotropic magnetic material isthe same as the second anisotropic magnetic material.

Another aspect of the invention is directed to a structure comprising: asemiconductor integrated circuit comprising a multilevel wiring networkdisposed on a substrate; an inductor integrated into said multilevelwiring network, said inductor comprising a planar laminated magneticcore and a conductive winding that turns around in a generally spiralmanner on the outside of said planar laminated magnetic core, saidplanar laminated magnetic core comprising an alternating sequence of amagnetic layer and a non-magnetic layer; a first magnetic flux closurelayer disposed within about 100 μm of a face of the planar laminatedmagnetic core; and a second magnetic flux closure layer disposed withinabout 100 μm of an opposing face of the planar laminated magnetic core,the face and the opposing face parallel to a principal plane of theplanar laminated magnetic core.

In one or more embodiments, the conductive winding is disposed betweenthe planar laminated magnetic core and each magnetic flux closure layer.In one or more embodiments, the first magnetic flux closure layerextends across a length and a width of the face of the planar laminatedmagnetic core and the second magnetic flux closure layer extends acrossa length and a width of the opposing face of the planar laminatedmagnetic core, the respective length and the width measured with respectto the principal plane of the planar laminated magnetic core. In one ormore embodiments, the first magnetic flux closure layer extends beyondthe length and the width of the face of the planar laminated magneticcore. In one or more embodiments, the second magnetic flux closure layerextends beyond the length and the width of the opposing face of theplanar laminated magnetic core.

In one or more embodiments, the face of the planar laminated magneticcore is closer to the substrate than the opposing face of the planarlaminated magnetic core; wire segments in at least one wiring plane inthe multilevel wiring network are disposed between the inductor and thesubstrate; and the first magnetic flux closure layer is disposed betweenthe inductor and the wire segments in the at least one wiring plane. Inone or more embodiments, the first magnetic flux closure layer providesa low magnetic reluctance path for an inductor magnetic flux. In one ormore embodiments, the first magnetic flux closure layer prevents theinductor magnetic flux from passing through any wire segments in the atleast one wiring plane.

In one or more embodiments, the first and second magnetic flux closurelayers comprise the same material as the magnetic layers In one or moreembodiments, the planar laminated magnetic core and the first magneticflux closure layer are configured so that a first magnetic flux passesthrough a first magnetic layer in the planar laminated magnetic core ina first direction that is parallel to a first hard axis of magnetizationof the first magnetic layer and the first magnetic flux passes throughthe first magnetic flux closure layer in a second direction that isparallel to a second hard axis of magnetization of the first magneticflux closure layer. In one or more embodiments, the planar laminatedmagnetic core and the second magnetic flux closure layer are configuredso that a second magnetic flux passes through a second magnetic layer inthe planar laminated magnetic core in a third direction that is parallelto a third easy axis of magnetization of the second magnetic layer andthe second magnetic flux passes through the second magnetic flux closurelayer in a fourth direction that is parallel to a fourth easy axis ofmagnetization of the second magnetic flux closure layer.

In one or more embodiments, each magnetic layer in the planar laminatedmagnetic core comprises a first anisotropic magnetic material, the firstmagnetic flux closure layer comprises a second anisotropic magneticmaterial, and the second magnetic flux closure layer comprises a thirdanisotropic magnetic material, the first, second, and third anisotropicmagnetic materials having a respective hard axis of magnetization thatis at least partially aligned with an axis of the conductive winding,the conductive winding extending along the axis of the conductivewinding. In one or more embodiments, the first, second, and thirdanisotropic magnetic materials are the same.

Another aspect of the invention is directed to an inductor comprising aplanar laminated magnetic core comprising an alternating sequence of (a)a magnetic layer having a thickness of about 100 angstroms to about10,000 angstroms and (b) a non-magnetic layer having a thickness ofabout 10 angstroms to about 2,000 angstroms, the thicknesses of themagnetic and non-magnetic layers measured along an axis that isorthogonal to a principal plane of the planar magnetic core, wherein theplanar laminated magnetic core is configured so that a magnetic fluxpasses through a first magnetic layer in a first direction that isparallel to a first easy axis of magnetization of the first magneticlayer and the magnetic flux passes through a second magnetic layer in asecond direction that is parallel to a second easy axis of magnetizationof the second magnetic layer, wherein the second magnetic layer is aneighboring magnetic layer of the first magnetic layer, and the firstdirection is opposite to the second direction, whereby the magnetic fluxhas a closed path that extends through the first and second magneticlayers parallel to the first and second easy axes of magnetization,respectively; and a conductive winding that turns around in a generallyspiral manner on the outside of said planar laminated magnetic core.

In one or more embodiments, the non-magnetic layer comprises anelectrically insulating material. In one or more embodiments, theinductor further comprises a final magnetic layer disposed on a finalnon-magnetic layer, the final non-magnetic layer in the alternatingsequence; and a capping layer disposed on the final magnetic layer on afirst side of the planar laminated magnetic core. In one or moreembodiments, the capping layer comprises silicon, tantalum, aluminum,chromium, cobalt, titanium, zirconium, or a combination of two or moreof the foregoing. In one or more embodiments, the inductor furthercomprises an adhesion layer disposed below a final magnetic layer on asecond side of the planar laminated magnetic core, wherein the adhesionlayer and the capping layer comprise the same material, and the firstand second sides are on opposite sides of the planar laminated magneticcore. In one or more embodiments, the adhesion and capping layerscomprise silicon, tantalum, aluminum, chromium, cobalt, titanium,zirconium, or a combination of two or more of the foregoing.

In one or more embodiments, the planar laminated magnetic core isfurther configured so that a second magnetic flux passes through thefirst magnetic layer in the first direction and through a third magneticlayer in a second direction that is parallel to a third easy axis ofmagnetization of the third magnetic layer, wherein the third magneticlayer is a second neighboring magnetic layer of the first magnetic layersuch that the first magnetic layer is disposed between the second andthird magnetic layers, whereby the second magnetic flux has a closedpath that passes through the first and third magnetic layers parallel tothe first and third easy axes of magnetization, respectively. In one ormore embodiments, the inductor further comprises a final magnetic layerdisposed on a last non-magnetic layer on a first side of the planarmagnetic core, the last non-magnetic layer in the alternating sequence,wherein the alternating sequence includes a first magnetic layer on asecond side of the planar magnetic core, and wherein the first and finalmagnetic layers have a first thickness and the other magnetic layers inthe alternating sequence have a second thickness, the first thicknessbeing one half of the second thickness.

In one or more embodiments, the magnetic layer comprises an anisotropicmagnetic material having a hard axis of magnetization that is at leastpartially aligned with an axis of the conductive winding, the conductivewinding extending along the axis.

Another aspect of the invention is directed to an inductor comprising: aplanar laminated magnetic core comprising an alternating sequence of (a)a magnetic layer having a thickness of about 100 angstroms to about10,000 angstroms and (b) a non-magnetic layer having a thickness ofabout 10 angstroms to about 2,000 angstroms, the thicknesses of themagnetic and non-magnetic layers measured along an axis that isorthogonal to a principal plane of the planar magnetic core, wherein theplanar laminated magnetic core is configured so that a magnetic fluxpasses through a first magnetic layer in a first direction that isparallel to a first easy axis of magnetization of the first magneticlayer and the magnetic flux passes through a second magnetic layer in asecond direction that is parallel to a second easy axis of magnetizationof the second magnetic layer, wherein the second magnetic layer is aneighboring magnetic layer of the first magnetic layer, and the firstdirection is opposite to the second direction, whereby the magnetic fluxhas a closed path that extends through the first and second magneticlayers parallel to the first and second easy axes of magnetization,respectively; a first orthogonal magnetic layer disposed laterally fromthe planar magnetic core, the first orthogonal magnetic layer orthogonalto the principal plane; and a conductive winding that turns around in agenerally spiral manner on the outside of said planar laminated magneticcore.

In one or more embodiments, the closed path of the magnetic flux extendsthrough at least a portion of the first orthogonal magnetic layer. Inone or more embodiments, the first orthogonal magnetic layer is disposedin a hole between first and second portions of a first orthogonalnon-magnetic layer. In one or more embodiments, a height of the firstorthogonal magnetic layer is approximately equal to a height of theplanar magnetic core, the respective height measured with respect to theaxis. In one or more embodiments, each magnetic layer in the planarlaminated magnetic core comprises an anisotropic magnetic materialhaving a hard axis of magnetization that is at least partially alignedwith an axis of the conductive winding, the conductive winding extendingalong the axis of the conductive winding. In one or more embodiments,the hard axis of magnetization of the first magnetic layer is orthogonalto the easy axis of magnetization of the first magnetic layer.

In one or more embodiments, the inductor further comprises a secondorthogonal magnetic layer disposed laterally from the planar magneticcore such that the planar magnetic core is disposed between the firstand second orthogonal magnetic layers, the second orthogonal magneticlayer orthogonal to the principal plane. In one or more embodiments, theclosed path of the magnetic flux extends through at least a portion ofthe first and second orthogonal magnetic layers. In one or moreembodiments, the magnetic flux passes through the first orthogonalmagnetic layer in a first orthogonal direction that is parallel to aneasy axis of magnetization of the first orthogonal magnetic layer andthe magnetic flux passes through the second orthogonal magnetic layer ina second orthogonal direction that is parallel to an easy axis ofmagnetization of the second orthogonal magnetic layer, the firstorthogonal direction opposite to the second orthogonal direction.

In one or more embodiments, the first orthogonal magnetic layer isdisposed in a hole between first and second portions of a firstorthogonal non-magnetic layer and the second orthogonal magnetic layeris disposed in a hole between first and second portions of a secondorthogonal non-magnetic layer. In one or more embodiments, a height ofthe first and second orthogonal magnetic layers is approximately equalto a height of the planar magnetic core, the respective height measuredwith respect to the axis. In one or more embodiments, each magneticlayer in the planar laminated magnetic core comprises an anisotropicmagnetic material having a hard axis of magnetization that is at leastpartially aligned with an axis of the conductive winding, the conductivewinding extending along the axis of the conductive winding.

Another aspect of the invention is directed to a structure comprising: asemiconductor integrated circuit comprising a multilevel wiring network;and an inductor integrated into said multilevel wiring network, saidinductor comprising a planar laminated magnetic core and a conductivewinding that turns around in a generally spiral manner on the outside ofsaid planar laminated magnetic core, said planar laminated magnetic corecomprising an alternating sequence of a magnetic layer and anon-magnetic layer, wherein the magnetic layer comprises a ferromagneticalloy having an iron composition of about 10 atomic percent to about 90atomic percent.

In one or more embodiments, the inductor core has a saturationmagnetization of at least 1.5 T. In one or more embodiments, theinductor has a coercivity of less than or equal to 1.0 Oe. In one ormore embodiments, the ferromagnetic alloy comprises CoFeB, CoFe, or acombination thereof. In one or more embodiments, the magnetic layerfurther comprises at least one additional ferromagnetic material thatdoes not include iron. In one or more embodiments, the at least oneadditional ferromagnetic material includes cobalt, nickel, or acombination thereof.

In one or more embodiments, the magnetic layer further comprises boron,tantalum, chromium, cobalt, titanium, zirconium, or a combination of twoor more of the foregoing. In one or more embodiments, the non-magneticlayer comprises an electrical insulator layer and a first interfacelayer, wherein the non-magnetic layer is disposed between a firstmagnetic layer and a second magnetic layer. In one or more embodiments,the interface layer comprises tantalum, aluminum, chromium, cobalt,titanium, zirconium, silicon, or a combination of two or more of theforegoing. In one or more embodiments, the electrical insulatorcomprises silicon dioxide (SiO₂), aluminum oxide (Al_(x)O_(y)), chromiumoxide (Cr_(x)O_(y)), cobalt oxide (Co_(x)O_(y)), tantalum oxide(Ta_(x)O_(y)), titanium oxide (Ti_(x)O_(y)), silicon nitride(Si_(x)N_(y)), aluminum nitride (Al_(x)N_(y)), tantalum nitride(Ta_(x)N_(y)), or a combination of two or more of the foregoing. In oneor more embodiments, the electrical insulator comprises an oxide of atleast a portion of the material that forms the magnetic layer.

In one or more embodiments, the magnetic layer comprises an anisotropicmagnetic material having a hard axis of magnetization that is at leastpartially aligned with an axis of the conductive winding, the conductivewinding extending along the axis of the conductive winding.

Another aspect of the invention is directed to a microelectronic devicecomprising: a semiconductor integrated circuit, wherein saidsemiconductor integrated circuit comprises a multilevel wiring network,wherein said semiconductor integrated circuit operates with a pluralityof DC supply voltages; and a DC to DC voltage converter which deliversat least one of said DC supply voltages for said semiconductorintegrated circuit, said DC to DC voltage converter comprising aninductor, and wherein said inductor is integrated thereinto saidmultilevel wiring network, wherein said inductor comprises a planarmagnetic core and a conductive winding, wherein said conductive windingturns around in generally spiral manner on the outside of said planarmagnetic core, said planar magnetic core having a laminatedconfiguration comprising at least one magnetic layer and at least onecurrent rectifying layer, wherein the magnetic layer comprises aferromagnetic alloy having an iron composition of about 10 atomicpercent to about 90 atomic percent.

In one or more embodiments, the current rectifying layer comprises ap-type semiconductor, the p-type semiconductor having a first workfunction less than a second work function of the magnetic material. Inone or more embodiments, the laminated configuration further comprisesan interface metal layer disposed on said p-type semiconductor, theinterface layer having a work function less than said first workfunction of said p-type semiconductor. In one or more embodiments, themicroelectronic device further comprises a second magnetic layerdisposed on said interface metal layer, the second magnetic layercomprising the ferromagnetic alloy.

In one or more embodiments, the current rectifying layer comprises an-type semiconductor, the n-type semiconductor having a first workfunction greater than a second work function of the magnetic material.In one or more embodiments, the laminated configuration furthercomprises an interface metal layer disposed on said n-typesemiconductor, the interface layer having a work function greater thansaid first work function of said n-type semiconductor. In one or moreembodiments, the microelectronic device further comprises a secondmagnetic layer disposed on said interface metal layer, the secondmagnetic layer comprising the ferromagnetic alloy.

In one or more embodiments, the magnetic layer further comprises atleast one additional ferromagnetic material that does not include iron.In one or more embodiments, the at least one additional ferromagneticmaterial includes cobalt, nickel, or a combination thereof. In one ormore embodiments, the inductor and at least a portion of thesemiconductor integrated circuit form a transformer. In one or moreembodiments, the inductor and at least a portion of the semiconductorintegrated circuit form a power converter. In one or more embodiments,the inductor and at least a portion of the semiconductor integratedcircuit form a microprocessor.

In one or more embodiments, the magnetic layer comprises an anisotropicmagnetic material having a hard axis of magnetization that is at leastpartially aligned with an axis of the conductive winding, the conductivewinding extending along the axis of the conductive winding.

Another aspect of the invention is directed to an inductor comprising: aplanar laminated magnetic core comprising an alternating sequence of amagnetic layer and a non-magnetic layer, wherein the non-magnetic layercomprises an insulating layer disposed between first and secondinterface layers; and a conductive winding that turns around in agenerally spiral manner on the outside of said planar laminated magneticcore.

In one or more embodiments, the first and second interface layerscomprise a material and the insulating layer comprises a compound of (a)the material and (b) oxygen, nitrogen, or a combination thereof. In oneor more embodiments, the insulating layer has a root mean squaredroughness of less than or equal to 20 angstroms. In one or moreembodiments, the first and second interface layers comprise a materialthat includes silicon, tantalum, aluminum, chromium, cobalt, titanium,zirconium, or a combination of two or more of the foregoing. In one ormore embodiments, the insulating layer comprises a compound of thematerial and oxygen. In one or more embodiments, the insulating layercomprises a compound of the material and nitrogen. In one or moreembodiments, the insulating layer comprises a compound of the material,oxygen, and nitrogen.

In one or more embodiments, the non-magnetic layer comprises (a)silicon, tantalum, aluminum, chromium, cobalt, titanium, or zirconiumand (b) oxygen, and the first and second interface layers reduce a firstroot mean squared roughness and a second root mean squared roughness toless than or equal to 20 angstroms, the first root mean squaredroughness at an interface between a first magnetic layer and the firstinterface layer, the second root mean squared roughness at an interfacebetween a second magnetic layer and the second interface layer. In oneor more embodiments, the non-magnetic layer comprises (a) silicon,tantalum, aluminum, chromium, cobalt, titanium, or zirconium and (b)nitrogen, and the first and second interface layers reduce a first rootmean squared roughness and a second root mean squared roughness to lessthan or equal to 20 angstroms, the first root mean squared roughness atan interface between a first magnetic layer and the first interfacelayer, the second root mean squared roughness at an interface between asecond magnetic layer and the second interface layer. In one or moreembodiments, the non-magnetic layer comprises (a) silicon, tantalum,aluminum, chromium, cobalt, titanium, or zirconium and (b) oxygen andnitrogen, and the first and second interface layers reduce a first rootmean squared roughness and a second root mean squared roughness to lessthan or equal to 20 angstroms, the first root mean squared roughness atan interface between a first magnetic layer and the first interfacelayer, the second root mean squared roughness at an interface between asecond magnetic layer and the second interface layer.

In one or more embodiments, the first and second interface layersinhibit a diffusion of oxygen, nitrogen, or a combination thereof fromthe insulating layer into a neighboring magnetic layer. In one or moreembodiments, the magnetic layer comprises an anisotropic magneticmaterial having a hard axis of magnetization that is at least partiallyaligned with an axis of the conductive winding, the conductive windingextending along the axis of the conductive winding.

In one or more embodiments, the inductor further comprises a finalmagnetic layer disposed on a last non-magnetic layer, the lastnon-magnetic layer in the alternating sequence; and a capping layerdisposed on the final magnetic layer on a first side of the planarlaminated magnetic core, wherein the capping layer and the first andsecond interface layers comprise the same material. In one or moreembodiments, the inductor further comprises an adhesion layer disposedbelow a final magnetic layer on a second side of the planar laminatedmagnetic core, wherein the adhesion layer and the first and secondinterface layers comprise the same material, and the first and secondsides are on opposite sides of the planar laminated magnetic core.

Another aspect of the invention is directed to a microelectronic devicecomprising: a semiconductor integrated circuit comprising a multilevelwiring network; and an inductor integrated into said multilevel wiringnetwork, said inductor comprising a planar laminated magnetic core and aconductive winding that turns around in a generally spiral manner on theoutside of said planar laminated magnetic core, said planar laminatedmagnetic core comprising an alternating sequence of a magnetic layer anda non-magnetic layer, wherein the non-magnetic layer comprises aninsulating layer disposed between first and second interface layers.

In one or more embodiments, the inductor and at least a portion of thesemiconductor integrated circuit form a transformer. In one or moreembodiments, the inductor and at least a portion of the semiconductorintegrated circuit form a power converter. In one or more embodiments,the inductor and at least a portion of the semiconductor integratedcircuit form a microprocessor.

In one or more embodiments, the magnetic layer comprises an anisotropicmagnetic material having a hard axis of magnetization that is at leastpartially aligned with an axis of the conductive winding, the conductivewinding extending along the axis.

In one or more embodiments, the first and second interface layerscomprise a material and the insulating layer comprises a compound of (a)the material and (b) oxygen, nitrogen, or a combination thereof. In oneor more embodiments, the insulating layer has a root mean squaredroughness of less than or equal to 20 angstroms. In one or moreembodiments, the first and second interface layers comprise a materialthat includes silicon, tantalum, aluminum, chromium, cobalt, titanium,zirconium, or a combination of two or more of the foregoing. In one ormore embodiments, the insulating layer comprises a compound of thematerial and oxygen. In one or more embodiments, the insulating layercomprises a compound of the material and nitrogen. In one or moreembodiments, the insulating layer comprises a compound of the material,oxygen, and nitrogen.

In one or more embodiments, the non-magnetic layer comprises (a)silicon, tantalum, aluminum, chromium, cobalt, titanium, or zirconiumand (b) oxygen, and the first and second interface layers reduce a firstroot mean squared roughness and a second root mean squared roughness toless than or equal to 20 angstroms, the first root mean squaredroughness at an interface between a first magnetic layer and the firstinterface layer, the second root mean squared roughness at an interfacebetween a second magnetic layer and the second interface layer. In oneor more embodiments, the non-magnetic layer comprises (a) silicon,tantalum, aluminum, chromium, cobalt, titanium, or zirconium and (b)nitrogen, and the first and second interface layers reduce a first rootmean squared roughness and a second root mean squared roughness to lessthan or equal to 20 angstroms, the first root mean squared roughness atan interface between a first magnetic layer and the first interfacelayer, the second root mean squared roughness at an interface between asecond magnetic layer and the second interface layer. In one or moreembodiments, the non-magnetic layer comprises (a) silicon, tantalum,aluminum, chromium, cobalt, titanium, or zirconium and (b) oxygen andnitrogen, and the first and second interface layers reduce a first rootmean squared roughness and a second root mean squared roughness to lessthan or equal to 20 angstroms, the first root mean squared roughness atan interface between a first magnetic layer and the first interfacelayer, the second root mean squared roughness at an interface between asecond magnetic layer and the second interface layer.

In one or more embodiments, the first and second interface layersinhibit a diffusion of oxygen, nitrogen, or a combination thereof fromthe insulating layer into a neighboring magnetic layer. In one or moreembodiments, the microelectronic device further comprises a finalmagnetic layer disposed on a last non-magnetic layer, the lastnon-magnetic layer in the alternating sequence; and a capping layerdisposed on the final magnetic layer on a first side of the planarlaminated magnetic core, wherein the capping layer and the first andsecond interface layers comprise the same material. In one or moreembodiments, the microelectronic device further comprises an adhesionlayer disposed on a first magnetic layer on a second side of the planarlaminated magnetic core, the second side of the planar magnetic coredisposed closer to a semiconductor substrate in the semiconductorintegrated circuit than the first side of the planar magnetic core, theadhesion layer and the interface layers comprising the same material.

Another aspect of the invention is directed to a method of manufacturingcomprising: depositing a magnetic material over a semiconductorsubstrate to form a magnetic layer, wherein at least a portion of amultilevel wiring network is formed on the semiconductor substrate; in aphysical vapor deposition (PVD) chamber, depositing a non-magnetic layeron the magnetic layer, wherein said non-magnetic layer is formed by:depositing an interface material to form a first interface layer on themagnetic layer; flowing a reactive gas into the PVD chamber, whilecontinuing to deposit the interface material, to form an insulatingmaterial on the first interface layer, the insulating layer comprising acompound of the interface material and the reactive gas; and stoppingthe reactive gas flow into the PVD chamber, while continuing to depositthe interface material, to form a second interface layer on theinsulating layer; repeating in alternate fashion, up to 100 times each,(a) the depositing of the magnetic material and (b) the depositing ofthe non-magnetic layer to form an alternating sequence of magneticlayers and non-magnetic layers; depositing the magnetic material on thelast non-magnetic layer in the sequence to form a final magnetic layer,resulting in a magnetic member with a laminated configuration; maskingand patterning said magnetic member in such a manner that after saidpatterning a remaining portion of said magnetic member comprises aplanar magnetic core; and forming a conductive winding around the planarmagnetic core, the conductive winding comprising wire segments andvertical interconnect accesses (VIAs), wherein said wire segmentspertain to at least two wiring planes in said multilevel wiring networkand said VIAs interconnect the at least two wiring planes.

In one or more embodiments, the interface layer comprises silicon,tantalum, aluminum, chromium, cobalt, titanium, zirconium, or acombination of at least two of the foregoing. In one or moreembodiments, the reactive gas comprises oxygen, nitrogen, or acombination thereof.

In one or more embodiments, the method further comprises reducing afirst root mean squared roughness and a second root mean squaredroughness to less than or equal to 20 angstroms, the first root meansquared roughness at an interface between a first magnetic layer and thefirst interface layer, the second root mean squared roughness at aninterface between a second magnetic layer and the second interfacelayer. In one or more embodiments, the method further comprisesdepositing the interface material on the final magnetic layer on a firstside of the planar magnetic core to form a capping layer. In one or moreembodiments, the method further comprises depositing the interfacematerial on a first magnetic layer on a second side of the planarmagnetic core to form an adhesion layer.

In one or more embodiments, the method further comprises integrating theinductor into the multilevel wiring network in a semiconductorintegrated circuit. In one or more embodiments, the method furthercomprises forming a transformer that comprises the inductor and at leasta portion of the semiconductor integrated circuit. In one or moreembodiments, the method further comprises forming a power converter thatcomprises the inductor and at least a portion of the semiconductorintegrated circuit. In one or more embodiments, the method furthercomprises forming a microprocessor that comprises the inductor and atleast a portion of the semiconductor integrated circuit.

In one or more embodiments, the method further comprises exposing thesubstrate to an external magnetic field during the depositing of themagnetic material to form each magnetic layer; and inducing a magneticanisotropy in each magnetic layer. In one or more embodiments, themethod further comprises placing the substrate on a permanent magneticfilm; and during the depositing of the magnetic material, generating theexternal magnetic field from the permanent magnetic film. In one or moreembodiments, the method further comprises placing a permanent magnetproximal to a substrate deposition location in a magnetic materialdeposition chamber, the permanent magnet generating the externalmagnetic field; and disposing the substrate on the substrate depositionlocation; wherein a surface of the permanent magnet is disposed about 1mm to about 5 mm from a surface of the substrate, whereby the externalmagnetic field is concentrated at the surface of the substrate. In oneor more embodiments, the method further comprises inducing a hard axisof magnetization in each magnetic layer, the hard axis at leastpartially aligned with an axis of the conductive winding, the conductivewinding extending along the axis of the conductive winding.

In one or more embodiments, the method further comprises after formingthe magnetic member with the laminated configuration: exposing thesubstrate to an external magnetic field; during the exposing thesubstrate to the external magnetic field, heating the substrate to about200° C. to about 400° C. for at least 30 minutes; and inducing amagnetic anisotropy in each magnetic layer in the magnetic member. Inone or more embodiments, the method further comprises inducing a hardaxis of magnetization in each magnetic layer, the hard axis at leastpartially aligned with an axis of the conductive winding, the conductivewinding extending along the axis of the conductive winding.

In the foregoing specification, the invention has been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the present invention as set forthin the claims below. Accordingly, the specification and figures are tobe regarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope ofpresent invention.

In addition, any specified material or any specified dimension of anystructure described herein is by way of example only. Furthermore, aswill be understood by those skilled in the art, the structures describedherein may be made or used in the same way regardless of their positionand orientation. Accordingly, it is to be understood that terms andphrases such as “under,” “upper,” “side,” “over,” “underneath,”“parallel,” “perpendicular,” “vertical,” “lateral,” etc., as used hereinrefer to relative location and orientation of various portions of thestructures with respect to one another, and are not intended to suggestthat any particular absolute orientation with respect to externalobjects is necessary or required.

The foregoing specification also describes processing steps. It isunderstood that the sequence of such steps may vary in differentembodiments from the order that they were detailed in the foregoingspecification. Consequently, the ordering of processing steps in theclaims, unless specifically stated, for instance, by such adjectives as“before,” “ensuing,” “after,” etc., do not imply or necessitate a fixedorder of step sequence.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any element(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature, or element, of any or all the claims.

Many modifications and variations of the present invention are possiblein light of the above teachings, and could be apparent for those skilledin the art. The scope of the invention is defined by the appendedclaims.

What is claimed is:
 1. A structure comprising: a semiconductorintegrated circuit comprising a multilevel wiring network disposed on asubstrate; an inductor integrated into said multilevel wiring network,said inductor comprising a planar laminated magnetic core and aconductive winding that turns around in a generally spiral manner on theoutside of said planar laminated magnetic core, said planar laminatedmagnetic core comprising an alternating sequence of a magnetic layer anda non-magnetic layer; a first magnetic flux closure layer disposedwithin about 100 μm of a face of the planar laminated magnetic core; anda second magnetic flux closure layer disposed within about 100 μm of anopposing face of the planar laminated magnetic core, the face and theopposing face parallel to a principal plane of the planar laminatedmagnetic core, wherein: the planar laminated magnetic core and the firstmagnetic flux closure layer are configured so that a first magnetic fluxpasses through a first magnetic layer in the planar laminated magneticcore in a first direction that is parallel to a first hard axis ofmagnetization of the first magnetic layer and the first magnetic fluxpasses through the first magnetic flux closure layer in a seconddirection that is parallel to a second hard axis of magnetization of thefirst magnetic flux closure layer, and the planar laminated magneticcore and the second magnetic flux closure layer are configured so that asecond magnetic flux passes through a second magnetic layer in theplanar laminated magnetic core in a third direction that is parallel toa third hard axis of magnetization of the second magnetic layer and thesecond magnetic flux passes through the second magnetic flux closurelayer in a fourth direction that is parallel to a fourth hard axis ofmagnetization of the second magnetic flux closure layer.
 2. Thestructure of claim 1, wherein the conductive winding is disposed betweenthe planar laminated magnetic core and each magnetic flux closure layer.3. The structure of claim 1, wherein the first magnetic flux closurelayer extends across a length and a width of the face of the planarlaminated magnetic core and the second magnetic flux closure layerextends across a length and a width of the opposing face of the planarlaminated magnetic core, the respective length and the width measuredwith respect to the principal plane of the planar laminated magneticcore.
 4. The structure of claim 3, wherein the first magnetic fluxclosure layer extends beyond the length and the width of the face of theplanar laminated magnetic core.
 5. The structure of claim 4, wherein thesecond magnetic flux closure layer extends beyond the length and thewidth of the opposing face of the planar laminated magnetic core.
 6. Thestructure of claim 1, wherein the face of the planar laminated magneticcore is closer to the substrate than the opposing face of the planarlaminated magnetic core; wire segments in at least one wiring plane inthe multilevel wiring network are disposed between the inductor and thesubstrate; and the first magnetic flux closure layer is disposed betweenthe inductor and the wire segments in the at least one wiring plane. 7.The structure of claim 6, wherein the first magnetic flux closure layerprovides a low magnetic reluctance path for an inductor magnetic flux.8. The structure of claim 7, wherein the first magnetic flux closurelayer prevents the inductor magnetic flux from passing through any wiresegments in the at least one wiring plane.
 9. The structure of claim 1,wherein the first and second magnetic flux closure layers comprise thesame material as the magnetic layers.
 10. The structure of claim 1,wherein each magnetic layer in the planar laminated magnetic corecomprises a first anisotropic magnetic material, the first magnetic fluxclosure layer comprises a second anisotropic magnetic material, and thesecond magnetic flux closure layer comprises a third anisotropicmagnetic material, the first, second, and third anisotropic magneticmaterials having a respective hard axis of magnetization that is atleast partially aligned with an axis of the conductive winding, theconductive winding extending along the axis of the conductive winding.11. The structure of claim 10, wherein the first, second, and thirdanisotropic magnetic materials are the same.